How many people speak southwest dialect in Yunnan?

Southwest dialect is spoken by 270 million people in Yunnan. As many as 270 million people use Southwest Mandarin, which is the most widely used and populous dialect in Mandarin. Historians believe that Southwest Mandarin is an extension of Jianghuai Mandarin, which is related to its origin and belongs to southern Mandarin, because according to historical research, the formation of Southwest Mandarin is a mandarin dialect gradually formed from the Ming Dynasty due to immigration to the southwest, and immigration is the main factor in the formation of Southwest Mandarin.