According to Mission, Ministry, and Money an article in New World Outlook written by Scott Brewer:
In looking at the ways congregations have spent their money over the last decade, a few patterns emerge. Churches spend most of their money in support of the local congregation and the clergy in the United Methodist connection. These categories of expense--pastoral and lay staff salaries and benefits, and operations--accounted for about 85 percent of all church spending in 2008, except for building projects and debt service. That figure was up about 0.5 percent compared to 1998, though it was up about 5 percentage points compared to 1978. While local church statistics can tell us only part of our story, the data do indicate that churches continue to show a consistent willingness to send money outside their walls.
What is changing, however, is where our churches are sending that money. This remaining 15 percent of church spending is used for mission and ministries outside the local congregation and for denominational administration (which helps to pay for things like holding annual conference and general conference) and for the supervision of clergy through support of bishops and district superintendents.
Note: These stats are several years old, but I couldn't find newer ones easily enough to update this entry.