CREATE TABLE table_61772 ("Show" CLOB, "Date" CLOB, "Official ratings  ( millions ) " FLOAT, "Weekly rank" CLOB, "Share" CLOB)

When were the shares 39.1%?
SELECT "Date" FROM table_61772 WHERE "Share" = '39.1%'
SELECT "Date" FROM "table_61772" WHERE "Share" = '39.1%'