Bill Gates is once again the richest person on the planet, a title he’s held for 16 out of the last 21 years. He recaptured the top spot in March 2014 after a four-year run by Mexico’s Carlos Slim Helu as No. 1. Early on, the stellar performance of Microsoft, which he co-founded in 1975, boosted his net worth but he’s been steadily selling his shares in the software company for at least 15 years. He unloaded one third of his remaining stake over the 12 months through February 2015. That included a gift of shares worth $1.5 billion to The Bill & Melinda Gates Foundation in November 2014, which brought his lifetime giving up to $29.5 billion. Gates, who spends most of his time focused on philanthropy, laid out some decisive goals for his Bill & Melinda Gates Foundation in his annual January letter. While continuing to work on improving U.S. education and global health, the foundation is also committed to getting Africa to feed itself and wants to help spread mobile banking so that the poor can transform their lives.