2. Qatar

2. Qatar

Photograph by Aurore Belkin/Getty Images

Population: 1.9 million
Percentage of millionaire households: 14.3%

Qatar has the world's third-largest natural gas reserves and will host soccer's FIFA World Cup in 2022. It also counts about 47,000 millionaire households among its inhabitants. Oil and gas exports account for more than 50 percent of GDP and help to provide the Gulf state with the highest per-capita income after Liechtenstein. The Qatari ruler, Sheikh Hamad bin Khalifa al Thani, is also its richest inhabitant.

Data from: Boston Consulting Group and Bloomberg Billionaires