After more than 35 years painting my collection of 20mm figures has now reached 20,000 with the completion of some Norman and Breton cavalry (pictures to follow soon). I would have reached this figure earlier if I hadn't sold my Napoleonic Russian cavalry.
The breakdown by broad periods is
2,709 Lace wars
1,293 American Civil War
4,473 20th Century
Trouble is that it's a long way to the next milestone of 25K, so I won't achieve this for quite a few years.