I have no idea but it's in the thousands for sure. I lived in San Francisco in the pre aids 70s and early 80s, and averaged between 600 and 900 per year so go figure. At bath houses I'd often have five to ten partners in an evening, and lobed bath houses, toured Europe in the early 80s and visited the baths in every town or city I visited.
I also want to state I am a great advocate of recreational sex, but also an absolute believer in emotional sex. For the record my lover and I will celebrate our 40th anniversary in December. We have NEVER been monogomos, but we have ALWAYS lived by one rule, either one of us could sleep with anyone (male or female) once, the second time it had to be a three way.
Over the years we both have had serious sexual/romantic relationships with others, but I got to tell you, when you KNOW the guy you're with is the one who ultimately makes you happy, and that you also make him happy, there is never a threat to that relationship.
Don't be a puritan, enjoy the body God gave you.