It's well-known that men drink more than women—but a new analysis by a National Institutes of Health group finds that the gap between the way the two genders consume alcohol in the US is narrowing, according to an NIH press release.

For example, the percentage of females who drank alcohol in the previous 30 days went from 44.9 percent in 2002 to 48.3 percent in 2012, while the percentage of males went from 57.4 to 56.1 percent during the same time period.

Similarly, the average number of drinking days during the prior month went from 6.8 to 7.3 days for females, while going from 9.9 to 9.5 days for males.

"Males still consume more alcohol, but the differences between men and women are diminishing," says the lead researcher. The analysis looked at data from annual national surveys from 2002 to 2012.

Researchers looked at "lifetime abstinence, age of onset, current drinking, binge drinking, drinking and driving, reaching ... criteria for an alcohol use disorder, combining alcohol with other drugs such as marijuana, and other variables," and found that the gap between males and females narrowed, for all age groups or at least one age group, in all but one area: combining alcohol with pot "during the last drinking occasion." That behavior increased from 15 to 19 percent among males aged 18 to 25, but held steady at about 10 percent for females of the same age.

Researchers aren't sure why women are drinking more like men—they controlled for "recent trends in employment, pregnancy, [and] marital status"—but they say more study is needed, because women are at a higher risk for many alcohol-related health implications.

(Scientists have decided there are four kinds of drunks.)

This article originally appeared on Newser: American Women Are Drinking More Like Men

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