The last 3 out of 6 total (every one since 2012) have had > 50% of the votes for statehood: https://en.wikipedia.org/wiki/Puerto_Rico_political_status_p.... A fourth, in 1998, lost by only a couple percentage points to a 'none of the above' option.
And how many people voted?
Compare the people that voted on the referendum with the general elections held and you’ll see people boycott it.