“It was important to study handgun carrying because about 90 per cent of all firearm homicides and non-fatal firearm crimes for which the type of firearm is known are committed with a handgun,” said lead author Ali Rowhani-Rahbar, an associate professor of epidemiology at the University of Washington School of Public Health.

“An important first step to examining the consequences of firearm carrying at the national level is an accurate measurement of the occurrence of this behaviour and characterisation of those who engage in it.”

The data came from a 2015 nationally representative survey that assessed handgun-carrying behaviour of 1,444 gun owners.

“Compared with handgun owners who did not carry, those who did report carrying handguns tended to be younger, and more often male, live in the southern United States, have grown up in firearm-owning households, self-identify as politically conservative, and own more than one type of firearm,” said the report.

The survey found that 80 per cent of surveyed handgun owners who carried their handgun had a concealed-carry permit.

Two thirds said they always carried their handguns concealed, compared with 10 per cent who said they always carry their weapons openly.

Some owners reported carrying a concealed handgun without a permit in states in which doing so was illegal.

Nationwide, state laws on handgun carrying have generally become less restrictive over the last 30 years, said the study.

Co-authors on the study came from the Harvard School of Public Health, the University of Colorado and Northeastern University.