In 1990, how many players whose teams had the winning rate of more than 75%?
in 1990 refers to year = 1990; winning rate of more than 75% refers to Divide(won, games) > 0.75
SELECT COUNT(DISTINCT T1.playerID) FROM players_teams AS T1 INNER JOIN teams AS T2 ON T1.tmID = T2.tmID AND T1.year = T2.year WHERE CAST(T2.won AS REAL) * 100 / CAST(T2.games AS REAL) > 75 AND T1.year = 1990