It seems the number of close votes has increased:
Where's the documentation for this little bundle of joy?
As Arjan said below, this is the closest we're going to get for the documentation, currently.
As per Jeff:
The default # of close votes per day is 12.
I just noticed that SU and SF have been at 24 close votes per day per user since ... well, forever.
I'm going to go ahead and make 24 close votes per day the new default network-wide to start, and meanwhile it has been set to 50 for SO.
It is listed on the first answer to this question that has all the recent changes: