As part of its territory status, there is a set are certain goals and benchmarks that have to be met in order for Puerto Rico to become a state. One of those goals is a public vote on a statehood referendum. Puerto Rico has not just done this once—it's done this five times.
Puerto Ricos's most recent referendum vote was in 2017, with an overwhelming 97 percent of the island voting in favor of statehood.
Before that, in 2012, Puerto Rico held a two-part referendum vote. The first question asked whether Puerto Ricans should continue with the current political designation of the island as a territory, of which 54 percent of voters said "No." The second question asked what non-territorial option Puerto Ricans would prefer. The options were statehood, independence, or a sovereign nation in free association with the United States. Statehood received 61 percent of the vote, with sovereignty and independence receiving 33 and 5 percent of the vote, respectively., with almost 80 percent of the population voting in the referendum. 
Puerto Rico has met all of the qualifications to statehood and has voted multiple times in favor of formal statehood recognition, yet no bill or vote on the issue has been voted on in Congress.
Another referendum will be held this November, and is expected to pass.
Puerto Ricans have been overwhelmingly in favor of statehood for a long time. It's time for Congress to make good on their promise to vote in favor of a statehood resolution.