Lemon Chiffon Pie

1 Cup evaporated skim milk
1 (3oz.) pkg. lemon gelatin
1/3 Cup Sugar
1/8 Teaspoon salt
3/4 Cup boiling water
1 (6oz.) can frozen lemonade concentrate
Graham cracker crust for deep 10 inch pie
1 Small container non-dairy whipped topping
Chill smaller mixer bowl and beaters. Chill evaporated milk in freezer until ice crystals begin to form. Combine lemon gelatin sugar, salt and boiling water in a bowl. and stir until dissolved. Add lemonade concentrate. Stir until melted. Chill until thickened but not set. In the chilled bowl, whip evaporated milk until it is stiff and holds a peak. Fold in the gelatin mixture lightly thoroughly. Chill about 10 minutes. Turn into graham cracker pie shell. Chill at least 3 hours. Spread on non-dairy whipped topping.