Atlas of Giving: U.S. Charitable Giving Tops $450 Billion in 2014

Improved consumer confidence also played a role in giving growth. "Mood matters," Mitchell, said. "When consumers feel better about the economy, they tend to give more."

The report also cites low inflation and historically low interest rates as factors which contributed to a robust year of receipts for America's nonprofits. Other factors which contributed to the rise in giving include a continued surge in the number of new nonprofits and churches in the U.S., as well as an enormous increase in contributions to donor-advised fund accounts. In fact, the number of U.S. nonprofit organizations recognized by the IRS has grown 50 percent since 2003.