Well, you're ignoring the mathematical trend.

In 2005 there were 25 made guys. In 2007 there were 30. That's 5 new made guys in 2 years, or 2.5 per year.

So, if you follow the math, from 2005 to 2014 there were 9 years with 2.5 new made guys per year. That comes to 22.5 made guys.

Add 22.5 to the original number of 25 in 2005 and it comes to 47.5 made guys in 2014.

So there are 47.5 made guys in the Chicago Outfit