Total domestic sale for the year 2004-2008:
Commercial vehicles: 450 + 500 + 625 + 600 + 550 = 2725
Passenger vehicles: 700 + 675 + 900 + 1050 + 975 = 4300
Three wheelers: 300 + 350 + 400 + 375 + 350 = 1775
$\therefore$ Ratio of the total sale price of commercial vehicles, passenger vehicles and three wheelers = (5 $\times$ 2725) : (3 $\times$ 4300) : (2 $\times$ 1775) 
Contribution of commercial vehicles to the overall earnings = $\frac{(5\times 2725)}{(5\times 2725)+(3\times 4300)+(2\times 1775)}$ $\times 100$ $\approx$ 45%