Oslo Company prepared the following contribution format income statement based on a sales volume of $1,000$ units $($the relevant range of production is $500$ units to $1,500$ units$)$:

Sales $ $90,000$

Variable expenses $49,500$

Contribution margin $40,500$

Fixed expenses $33,210$

Net operating income $ $7,290$

$2.$ What is the contribution margin ratio?