How many played sims do you have in your game?

How many played sims do you have in your game? I usually play in only one save game with different families, which makes my sims count very high. Which are the highest number you ever reached and which problems come with it?

As much I love to have many own sims in my world, as much I don't want to have so many NPC's. I delete them every few sim-days, but they spawn like weed. I finally want to get rid of them, do you have an idea