At the end of the year, I will have been on Steam for 10 years. I just earned my 4000th achievements, so I earn about 8 achievements per week. Many of those must come in large lumps, because I do not play Steam games everyday, nor does everything generate achievements. Still, we all have those days when you complete a game and get seven achievements all at once for various options you chose along the way.
You have heard me have strong opinions about achievements in games. I apparently have some experience with them.