Preheat oven to 375 degrees. Mix together sugar, margarine, eggs. Stir in milk. In separate bowl, sift together flour, baking powder and salt. Stir egg mixture into dry ingredients. Gently fold in blueberries. Spread batter into greased and floured 9x13 pan. Mix together crumb topping ingredients in small bowl. Sprinkle batter with crumb topping. Bake until wooden toothpick poked into center comes out clean, 45 to 60 minutes.