According to the medical data I found in books and studies I read about 3 min as the average duration, when drunk 8 min.
Masters and Johnson found that men took about 4 minutes to reach orgasm with their partners
The truth is that the time between penetration and ejaculation varies not only from man to man, but from one time to the next for the same man." They added that the appropriate length for intercourse is the length of time it takes for both partners to be mutually satisfied, emphasizing that Kinsey "found that 75 percent of men ejaculated within two minutes of penetration.
A 2008 survey
of Canadian and American sex therapists stated that the average time for intromission was 7 minutes and that 1 to 2 minutes was too short, 3 to 7 minutes was adequate and 7 to 13 minutes desirable, while 10 to 30 minutes was too long.
I highlighted the word 'survey' because I guess they didn't measure the time with a clock but estimated it.