Significant falls in the number of abortions and of abortion facilities have been revealed in separate surveys.

According to a survey  by the Guttmacher Institute, a sexual and reproductive health policy body, abortion numbers have fallen to their lowest level since the mid-1970s and by 14 per cent since 2011 alone.

They are now below one million for the first time since 1975.

A second survey by the conservative Christian pro-life group Operation Rescue shows abortion facilities have also been steadily declining. In 1991, there were 2,176 surgical abortion facilities in the compared to 517 today, a decrease of 76 per cent. Since 2011, the numbero of facilities has declined by 23 per cent.

The Guttmacher Institute survey is released this week but is based on statistics up until the end of 2014.

At the same time, the UK's Christian Institute is reporting that pro-life Bill which bans abortions from taking place after 20 weeks of pregnancy has been passed in the US state of Kentucky. Kentucky Governor Matt Bevin, a Republican, signed the measure after it had been overwhelmingly approved in the state House and Senate. Bevin also signed a separate Bill that requires pregnant women to be given an ultrasound and receive a description of their unborn baby before going through with an abortion.

The American Civil Liberties Union, a radical pro-LGBT lobby group, has filed suit to challenge this pro-life measure.

Both surveys come shortly before Sunday's 44th anniversary of the contentious Roe v Wade Supreme Court decision in 1973 that disallowed any ban on abortion before the viability of the foetus, generally held to be at 24 weeks. Liberals fear there could be a Supreme Court attempt to overturn Roe v Wade under Donald Trump's administration.

Hillary Clinton's support for abortion was one of the factors that cost her the evangelical Christian vote.

In the third presidential debate during the campaign, Clinton said she supported the provisions set by Roe v Wade to regulate abortion on the basis of the life and health of the mother. Controversially, she added: "The kinds of cases that fall at the end of pregnancy are often the most heartbreaking, painful decisions for families to make."

No one is able however to give a definitive explanation for the decline.

Improvements in contraception are  believed to be among the reasons.

Megan Donovan, Guttmacher senior policy manager, said women should be empowered to access contraceptive services. "Empowering women to prevent unintended pregnancies and plan their families is both a human rights priority and smart public health policy," she said. 

Operation Rescue said the question no one seems to be able to definitively answer – and the authors of the survey did not address – is why?  

The organisation's president Troy Newman added: "When abortion clinics close, lives are saved.

"When there are no abortion businesses in a community actively marketing abortions to women, abortions decrease. Abortion businesses create a fake 'need' for women to get abortions through aggressive marketing campaigns. Take away the supply, and we find there is little actual demand."

There are currently more than 5,250 pregnancy help centres in the US that offer free assistance to pregnant women. These centres outnumber abortion facilities by more than 10 to one.