It could be that this number is global players (?), and you might not be able to see games in your region. Alternatively, most of the people are possibly in full games, and so don't show up on the list. More alternatively, it could be that this number are currently in L4D, some of which aren't in a game, and others which are in different game modes.
If I'm not wrong, Steam will show you servers near your location (i.e. low ping times). I think the "Download region" setting in Steam's Preferences/Settings might also affect what servers you see, so make sure that's set to what you want.
I had a lot of trouble finding games (at all) in my region.
The solution in my case was to join specific L4D steam groups in my country. Without that I would never find servers that were reasonably close. Automatically joining nearby games would often give me ridiculous ping times and inevitably kicked.
This is a serious flaw in an otherwise brilliant product.