You hear a lot about American generosity, and how we give a lot of money to charity ($241 billion a year from individuals in 2013). But there are some major asterisks we should attach to that number--each of which has implications for your budget.
(1) Of that $241 billion, over 30% goes to churches.
The number was 57% a decade ago. Why is the number so high, and why has it dropped? It's high because two of the biggest factors in motivating behavior are a shared social expectation and making it public, according to Penn professor Jonah Berger. Historically, the church has been very clear about an expectation that Christians tithe. They give 10% of their income to the church. That's what they do; it's not that they should, or we wish they would--it's part of the identity. Period. And that tithing has been public; they pass the plate every week and you can see the people around you doing it (who in turn can see you not doing it). From what I've seen, you can attribute the decline in church giving percentage pretty directly to two things; a decline in shared social expectations about what it means to be a Christian (with the individualization and commodification of the religion), and a decline in the significance of church in the life of even the average churchgoer (let alone the average American).
Nonprofit organizations that want to learn from the historical success of the church need to find ways to build shared social expectations about giving, and to make giving more public.
(2) Sacrificial giving is in decline.
It's not that people have stopped caring, but no single institution has the kind of hold on them the church used to have. Since nobody has stepped into the church's void in a consistent way, creating a shared social ethic of sacrificial giving (10% is a lot of money!), nonprofits that don't step up their efforts to attract and retain people in their 40s and 20s are likely to have budget problems in the near future. The last generation that had an ethic of sacrificial giving will only be giving for so much longer. That said, this isn't an irreversible trend--for example, households with incomes under $100k upped their giving (as percentage of income) in the last few years. The total dollar amount change wasn't significant since the recession lowered actual incomes, but it suggests people are still willing to be generous if given good reasons. Different things are considered to be the causes every decent person should give to (education giving is way up from a few years ago, instead of church)--and that's a communications opportunity for organizations willing to work together to drive interest in their mission area. City downtowns have figured out that everybody benefits when they market as a group; nonprofits could learn a thing or two from them.
(3) Models for giving are changing.
More people want to give time and talent; skilled volunteerism is up, as is volunteerism in general. If you're still on the model where "doing nonprofit work" is something for the professionals, and you think donors should give money and stay out of your hair, you're hurting yourself. Online giving has been rising very steadily the last few years--make sure your online donation form is RIDICULOUSLY quick and easy and visually appealing (if you can integrate it with Google or Apple Pay, all the better). Finally, the rising generations don't have the same unquestioning acceptance of big institutions their parents and grandparents did--institutional loyalty is way down. Driving and maintaining long-term interest in your cause is the big challenge for the next generation of development and communications directors--keep in mind that social connections and collaborative partnerships with supporters are both huge.