List of Americans by net worth

Columns: Rank | Name | Net worth ( USD ) | Age | Sources of wealth
9 | Steve Ballmer | $ 51.7 billion | 63 | Microsoft , LA Clippers | 10 | Jim Walton | $ 51.6 billion | 70 | Walmart , inherited | 11 | Alice Walton | $ 51.4 billion | 69 | Walmart , inherited | 12 | S. Robson Walton | $ 51.3 billion | 74 | Walmart , inherited | 13 | Charles Koch | $ 41 billion | 83 | Koch Industries | 13 | Julia Koch | $ 41 billion | 57 | Koch Industries , inherited | 15 | MacKenzie Bezos | $ 36.1 billion | 49 | Amazon , divorce

Example questions:
When was the Billionaire who obtain their wealth from a database software and technology born ? | How old is the Billionaire to earn their wealth from a company that now has almost 20,000 employees ? | Which university did the wealthiest American Billionaire attend ? | How old is the American Billionaire that co-founded a company with Paul Allen ? | At what age did the youngest American on the list become a billionaire by net worth ?

Answers:
August 17 , 1944 | 77 | Princeton University | 64 | 23