How many summer olympic sites are located within tropical regions?

As of 2021, there have been three Summer Olympic Games held in tropical regions: Mexico City in 1968, Seoul in 1988, and Rio de Janeiro in 2016. The tropical regions are defined as areas between the Tropic of Cancer and the Tropic of Capricorn. While other Olympic Games have been hosted in warm climates, these three are the only ones that fall entirely within the tropical zone.