CREATE TABLE table_16756 ("#" FLOAT, "Race Name" CLOB, "Circuit" CLOB, "Date" CLOB, "Winning driver" CLOB, "Constructor" CLOB, "Report" CLOB)

How many dates have silverstone circuit
SELECT COUNT("Date") FROM table_16756 WHERE "Circuit" = 'Silverstone'
SELECT COUNT("Date") FROM "table_16756" WHERE "Circuit" = 'Silverstone'