What percentage of oklahomans fled the state during the great depression and dust bowl years?

The Oklahoma was the 28th most populous city of United states and the people were known as Oklahomans meaning Red people. During great depression Okhloma suffered population loss because drought severely hit the region and completely destroyed agriculture and Economy as a result California received more than 2,50,000 poor migrants which headed the state in search of job and livelihood which was advertised in the city during dust bowl years and played very important role in changing the Economy of the country.