Regarding all of the articles cited:

First one: 50 members in 2000.

Second: 50 in 2002.

Third: 25 in 2005.

Fourth: 28 in 2007.

Fifth: 30 in 2007.

Sixth: 60 in 2009.

Everything is fairly consistent except for the Calabrese number. That's pretty compelling and I'd never heard it before. It seems odd that Calabrese identified 60 active made men in 2009 when estimates were significantly lower 5, 10 years ago, but that does appear to be what the article says. However, I am left wondering if something was lost in translation. He started cooperating in 2002 and had been in jail since 97.

He's viewed as extraordinarily reliable.