CREATE TABLE table_71125 ("Year" FLOAT, "Entrant" CLOB, "Chassis" CLOB, "Engine" CLOB, "Tyres" CLOB, "Points" FLOAT)

How many years were g Tyres and Minardi m187 used?
SELECT AVG("Year") FROM table_71125 WHERE "Tyres" = 'g' AND "Chassis" = 'minardi m187'
SELECT AVG("Year") FROM "table_71125" WHERE "Chassis" = 'minardi m187' AND "Tyres" = 'g'