Has the Indy 500 always been run on the last sunday in May?

From 1911-1970, the Indianapolis 500 was scheduled for May 30th, unless it fell on a Sunday. In those cases, it was scheduled for May 31st. From 1971-1972, it was scheduled for the Saturday of Memorial Day weekend. In 1973, it was scheduled for Monday, Memorial Day itself. Since 1974, it has been scheduled for Sunday, the day before Memorial Day.