A study suggests that 3.8 per cent of Americans are openly gay, bisexual or transgender.

At nine million people, this number is equivalent to the population of New Jersey.

However, the number of those who say they have engaged in same-sex relationships or sexual behaviour is twice as high as 8.2 per cent – or 19 million people.

Eleven per cent – 25.6 million people – have reported feeling attraction to the same sex, the study said.

The study was carried out by the Williams Institute at UCLA in California. Researchers cross-referenced five national and state popular surveys.

Slightly more people (1.8 per cent) identified as bisexual than lesbian or gay (1.7 per cent).

Approximately 700,000 people said they were transgender – 0.3 per cent.

Last September, a survey of 450,000 UK adults found that just 1.5 per cent were willing to identify themselves as lesbian, gay or bisexual.

Of the five per cent who did not say they were heterosexual, one per cent said they were gay or lesbian, 0.5 per cent said they were bisexual and 3.5 per cent refused to answer the question, described themselves as “other” or said they did not know.

Gay rights charity Stonewall and the UK government both use a figure of six per cent of the population being lesbian, gay or bisexual, which works out at 3.6 million people.