Past F1 champions from the Western Hemisphere

With Perez going to McLaren, let's look at past world champions from North and South America:

1997: Jacques Villeneuve
1988, 1990, 1991: Senna
1981, 1983, 1987: Piquet
1978: Mario Andretti
1972, 1974: Fittipaldi
1961: Phil Hill