According to Sun, those people are officially a small minority. For most games, they are less likely to be in your target market. Bear in mind you’re talking about people who are running software that is now 8 years old.
To the OP, I don’t see the point in a poll on this. There is only one answer - yes of course people still play applets. Millions of them play each day. Just do a brief bit of research with google into the people playing games on places like popcap and yahoo games, and if you like add in individual games like runescape.
But all those are like that for historic reasons, and tend to be old games. If you’re targetting portals, you’re unlikely to have any choice - you’ll only be allowed to use an applet - but otherwise new games shouldn’t generally be considering applets. Either use webstart, or something proprietary because some aspect of webstart is insufficient for your needs.