 Its competition includes The Coca-Cola Company's Mello Yello and Surge, and Dr Pepper Snapple Group's Sun Drop; Mountain Dew accounts for 80% of citrus soft drinks sold within the US.Tennessee bottlers Barney and Ally Hartman developed Mountain Dew as a mixer in the 1940s.Soft drinks were sold regionally in the 1930s, and the Hartmans had difficulty in Knoxville obtaining their preferred soda to mix with liquor, preferably whiskey, so the two developed their own.