Exactly how many expatriates are there? Of course, nobody knows for sure, but some good, educated guesses abound.

Whatever the true numbers are, a new report says certain sectors of the globe are expecting more in the coming years with challenging implications for those who minister to expats with international congregations.

Over 1,000 English-language congregations serve people living outside of their home country around the world. Most of those congregations are multi-denominational as well as multi-national, though some were started by denominational groups such as Presbyterian, Lutheran, Baptist and Anglican.

These international churches function in a language, usually English, not normally spoken in the host country. They have a majority of people from other countries, ie expatriates, and they have a multi-cultural mix and diversity with a more global perspective than congregations in home countries.

According to UN statistics, more than 200 million people were living outside of their home country in 2010. However, this number also included economic migrants and refugees.

In terms of outbound expatriation, as of 2009, the United Kingdom had the highest number of expatriates among OECD countries with more than three million British citizens living abroad according to Wikipedia. Some estimates point to 5.2 million US citizens living outside their home country.

Over 43 per cent of companies across Asia project an increase in cross-border traditional expatriate assignments in the next two years, according to an article in the May 2 issue of the Bangkok, Thailand, newspaper, The Nation.

And, 85 per cent of them expect to send their staff to posts in neighbouring Asian nations. Globally, 45 per cent of all international companies expect to send an increasing number of employees abroad to all parts of the world.

Those statistics offer an expanding opportunity for outreach by international churches, but also present a challenge in formulating ministries to meet the unique needs of third-culture members.

In analysing these trends the Talent Mobility Study by Towers Watson, a New York City-based global professional services company, warned that assignment failures among expats can largely be attributed to job performance issues and family or personal situations.

The most common reason given for an assignment failure by Asian companies was the assignee's family (53%) while among US companies family issues ranked second (52%) after job performance problems (68%).

The newspaper reported that "Asian-headquartered companies identify the employee's inability to adapt to the host country's culture, language barriers and inadequate infrastructure (healthcare/schools) in the host country as significant causes of assignment failures as well."

But, the report continued, most companies do not evaluate an employee's family situation when selecting candidates for international assignments, nor do they often provide support for the family as a means of minimising assignment failures. Only 15 per cent of US companies and 14 per cent of Asian companies take those situations into consideration.

The report concluded that companies need to develop innovative solutions and approaches to address the challenges.

Many international churches already offer that kind of support to expats, whether business people, diplomats, NGO workers, educators, missionaries or others living overseas.

"Every fall, when most of our new folks arrive, we have a several week Welcome to Beijing programme following our Sunday services," said Pastor Mark Blair who serves as the pastor of the 600-member Zhong Guan Cun daughter church of the Beijing (China) International Christian Fellowship. "This is a sit down in a circle, have a coffee, sharing time with long-term residents who are church leaders. Often the chat time follows with going to lunch together in a nearby restaurant."

Mr Blair said the church also produces a Welcome to Beijing booklet with language tips, maps, lists of restaurants, government offices, and other information that would be of interest to new expatriate residents.

There is what Blair called a "great economic boom" in China which has led to an increase in expats there in recent years. He also attributed the expansion to an interest in helping the growing church in China and the "generous amount of scholarships given by China to students from all over the world".

The Rev Scott Herr, pastor of the American Church in Paris (France), where 700 people worship each Sunday, uses a similar methodology. "We have been offering an orientation course to life in Paris called Bloom Where You're Planted for the past 40-some years," he said. "We also publish a book that is a survival kit encyclopedia of helpful information."

Rev Herr said that his church doubled in membership in recent years primarily by adding a third worship using contemporary music.

In Santiago, Chile, Pastor Samuel A Mateer also reports growth in the expat population propelled by "the demand on copper from China and India which means the mining industry has great demand for management level and above workers".

"Our women spend time at the grocery stores listening for English spoken and at international women's groups, looking for ways to help the new ladies adapt to their new culture," Mr. Mateer reported. "They invite them to church and to the women's Bible studies to give them a sense of being loved."

"They provide them someone who can talk their language and understand what they are facing with a maid they cannot talk to, a husband extremely busy, and a school with new demands," the pastor explained.

Rev. Mateer said that at his 100 member San Marcos International Church, a Presbyterian congregation, "We lose one third of the congregation each year due to transfer in business and new postings with the US embassy."

Jimmy Martin, an elder of the International Christian Fellowship in Oberursel (Frankfurt), Germany, affirmed the role of church women in helping expat spouses adapt to living in another country.

"Finding a 'home away from home' in a loving group of women who understand many of your own challenges is a tremendous help to moms and wives," he said. Mr Martin is also the General Secretary of the International Baptist Churches, an association of Baptist congregations in 27 countries.

Many overseas churches integrate cultural adaptation and expat issues into their regular weekly activities. Small groups, parenting and cross-cultural support ministries, counselling, language training and prayer groups all form a strong component of support for those who struggle with the issues of living and functioning well in a different culture. Many pastors also address those issues in sermons and study groups.

The International Church of Bangkok, Thailand, is one example where expatriate concerns are a natural part of its many ministries. "We address all these areas comprehensively and holistically through our worship and small groups ministries," explained Stewart Perry, the pastor of the 300 member congregation.

Among other issues frequently reported by pastors of expat churches are loneliness, culture shock, language-learning struggles, bureaucratic hassles and homesickness.