There are 11 Taureans in the richest 100, up from eight in 2017's list. They include: Facebook founder and CEO Mark Zuckerberg, worth $53.8 billion (£42.2bn); BMW heiress and Germany’s richest woman Susanne Klatten, worth $20.5 billion (£16.1bn); and Koch Industries vice president David Koch, worth $47.2 billion (£37bn).