Not that much; Whirlpool, Kenmore, Universal, Easy, GE, Hotpoint, Blackstone, Westinghouse and Philco at various points in time offered two speed wringer washers.
Maytag was the undisputed leader in USA when it came to wringer washers and they never offered two speeds.
One speed washers such as Maytag simply advised housewives to wash fine or delicate things for shorter periods of time. Am guessing many simply didn't trust their wringer washer for "nice things" and did them by hand.