Should I tell my new boyfriend how many lovers I’ve had?

We were chatting late one night, after a few drinks, and he asked me how many lovers I’d had. I fudged it, saying a lady never tells. I’ve been wondering, since, if I should stop being coy about my past sexual relationships. Or, are there certain things that are best left unsaid?
We live in a time where there is a lot of sexual freedom. Reported in the media at all levels — from TV, to radio, print and the internet — it’s now expected that we are sexually active from a young age, across a range of casual relationships.