[zdragnar]

I found a reference that the primary turnout was around 11%: http://www.gothamgazette.com/state/7774-a-closer-look-at-vot...

> With 98 percent of precincts reporting as of Wednesday, the State Board of Elections shows 27,826 registered Democrats cast votes in Tuesday’s primary in New York’s 14th District. With 235,745 registered Democrats as of April, according to the BOE, this comes out to a turnout of around 11.8 percent.

NYT shows roughly 150,000 votes in the 14th precinct for the actual election: https://www.nytimes.com/elections/results/new-york-house-dis...

The population of the district is around 712,000 https://ballotpedia.org/New_York%27s_14th_Congressional_Dist...

So, the actual percentage is indeed higher than 4%. Even still, it's quite low.