Here is an interesting stab at calculating the amount of tithing
revenue the church takes in in the US. If one assumes that 40% of LDS
members pay a full tithing, the church's US intake in 1990 would be
1,569,725,758. If you assume 30%, the intake would be 1,177,294,318.
He is looking for $110 to get access to more current data, if you feel
so inclined to donate.
A county-by-county map of tithing revenue can be viewed at
A state-by-state table can be viewed at
A county-by-county table of info on Utah LDS congregations, income and
so forth can be viewed at
A summary can be found here http://www.mormon-news.com/tithing/index.asp.