According to a new survey of religious groups, Jewish people are most in favour of equal marriage in the US.

The survey conducted by the Public Religion Research Institute was released on Wednesday.

It reports that Jewish people are the faith group most likely to support equal marriage, with 83% agreeing with it.

However, 7-in-10 (69%) of white evangelical Protestants and nearly 6-in-10 (59%) black Protestants oppose same-sex marriage equality. Only 27% of white evangelical Protestants and just 35% of black Protestants said that they support same-sex marriage.

Over half of the 4,509 Americans surveyed now support equal marriage. There is now a 53% majority in favour of marriage equality, a staggering contrast to 2003 when just 32% of Americans supported the idea.

In the US, there are now seventeen states that recognise equal marriage. It is however banned in 33 others.

Recently, US Attorney General Eric Holder said that the US Federal Government will recognise equal marriage whether or not it is recognised in individual states.

The survey estimates that around 20% of Americans are LGBT, a 6% difference to what the population of America believes it to be.

The area of the US with biggest opposition to equal marriage is in the South. On Monday, the organisation, Freedom to Marry launched a $1million campaign to turn opinions around.