I do not know of any published number for your question. The best we could do is assume some kind of baseline from annual donations to churches which is in the hundreds of billions annual in the us. A lot of that goes to pay staff, and cover facility costs. And this is the rub for your question.
In 2014 Religious Organizations received about $114.68 billion in donations ().
If you are just looking for program expenses targeted at the poor, the number will be quite low. But if you include the services provided by churches that are used by poor individuals the number becomes much higher. Churches provide everything from meals, tangible goods, child care, lodging, counseling, courses, career services, and more. All of those services would not show up on a balance sheet as outreach/service to poor individuals because they tend to just be a part of the life of the community.
There are also huge variations in approaches to ministries between different churches. Some provide more services and opportunities to enrich yourself than others of similar size/donation amount. But in general having a place of worship (church, mosque, temple, etc) in a neighborhood makes the neighborhood a better place.