Michael Dell

Lifetime donations: $1.1 billion
Net worth: $18.9 billion
Generosity Index: 6%
Michael Dell is the chairman and CEO of Dell computer company. Since 1999, he's been the director of the Michael and Susan Dell Foundation, which gives primarily to education, social and human services, arts and culture, and community-development causes.
Earlier this year, the foundation pledged to donate $25 million to fund the construction of a new teaching hospital in Austin, Texas.
Source: Wealth-X