Image copyright AP Image caption Only about half of Americans (49%) now favour execution for prisoners convicted of murder

The proportion of Americans who support the death penalty has fallen below half for the first time, according to a US study.

The Pew Research Center, which looks at social issues, found that belief in capital punishment was at its lowest for over four decades.

Only about half of Americans (49%) now favour execution for inmates convicted of murder, while 42% oppose it.

Support has dropped by 7% since March 2015, from 56%.

There has been a sizeable slump in public approval for state executions, which peaked during the mid-1990s.

In 1994, eight out of 10 Americans backed the death penalty, and under two in 10 were opposed to it.

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According to the Pew's findings, opposition to the death penalty is at its highest since 1972.

Previous Gallup polls have shown that support fell as low as 42% in 1966, but then rose gradually to hit 80% in 1994.

Since then, it has been gradually declining across almost all demographics.

Pew found that people who identified as Republican were more likely to agree with capital punishment for convicted murderers (72%), while 34% of Democrats shared that view.

Men were more likely to say they favoured the death penalty, at 55%, while 38% oppose it - but for women the number for and against was almost equal - 43% for, and 45% against.

Image copyright AP Image caption Belief in capital punishment is at its lowest for over four decades

A 57% majority of white people favour the death penalty for murderers (down from 63% last year).

But Black and Hispanic people support it at much lower rates, at 29% and 36% respectively.

Being younger and spending longer in formal education also made respondents less likely to support execution.

Among those aged 18 to 29, the level was 42% in favour, compared to 51% of those 30 and older.

Among Americans with at least a college degree, 43% backed the death penalty, while that rose to 51% for those without a degree.

The researchers surveyed 1,201 adults between 23 August and 23 September, 2016.

The prevailing trend mimics the shift seen across the Atlantic.

In Britain, support for the death penalty dropped below 50% for the first time in 2015, according to the NatCen British Social Attitudes Report.

The survey found 48% were in favour of capital punishment, which was abolished in the UK in the 1960s.