CREATE TABLE table_77790 ("Year" FLOAT, "Division" FLOAT, "League" CLOB, "Reg. Season" CLOB, "Playoffs" CLOB, "Open Cup" CLOB)

How many years was there a team that was part of the usisl pro league?
SELECT COUNT("Year") FROM table_77790 WHERE "League" = 'usisl pro league'
SELECT COUNT("Year") FROM "table_77790" WHERE "League" = 'usisl pro league'