GOTHENBURG, Sweden, July 9 (UPI) -- A 30-year study of 70-year-olds found sexual intercourse increased for married men from 52 percent to 68 percent -- at least in Sweden, researchers said.

Nils Beckman and colleagues at the University of Gothenburg in Sweden studied sexual attitudes among more than 1,500 seniors and interviewed them in 1971/1972, 1976/1977, 1992/1993 and 2000/2001 about their sex lives.

Over the 30-year study period the number of 70-year-olds reported sexual intercourse increased: from 38 percent to 56 percent for married women, from 30 percent to 54 percent for unmarried men and 0.8 to 12 percent for unmarried women.

In addition, the study, published in the British Medical Journal, found the number of women reporting high sexual satisfaction increased -- more women reported having an orgasm during sex and fewer reported never having had an orgasm.

However, while the proportion of women reporting low satisfaction with their sex lives decreased, the proportion of men reporting low satisfaction increased. The authors suggest this might be because it is now more acceptable for men to admit "failure" in sexual matters.

Both men and women blame men when sexual intercourse stops between them, Beckman said.