CREATE TABLE table_25641 ("Year" FLOAT, "Date" TEXT, "Driver" TEXT, "Manufacturer" TEXT, "Laps" FLOAT, "Miles  ( km ) " TEXT, "Race Time" TEXT, "Average Speed  ( mph ) " TEXT)

Name the number of year for june 30
SELECT COUNT("Year") FROM table_25641 WHERE "Date" = 'June 30'
SELECT COUNT("Year") FROM "table_25641" WHERE "Date" = 'June 30'