Jamaica is 20 times larger than Guam.
Area: 544 km2 World Factbook
Population: 161,001 (July 2014) World Factbook
Guam is an organized, unincorporated territory of the United States in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Wikipedia
Area: 10,991 km2 World Factbook
Population: 2,930,050 (July 2014) World Factbook
Jamaica is an island country situated in the Caribbean Sea, comprising the third-largest island of the Greater Antilles. Wikipedia