CREATE TABLE table_26945 ("Name" TEXT, "Position" TEXT, "Period" TEXT, "Appearances\\u00b9" FLOAT, "Goals\\u00b9" FLOAT, "Nationality\\u00b2" TEXT)

How many periods had 15 goals?
SELECT COUNT("Period") FROM table_26945 WHERE "Goals\u00b9" = '15'
SELECT COUNT("Period") FROM "table_26945" WHERE "Goals\u00b9" = '15'