They're not yearly salary to yearly rent - it's yearly salary to monthly rent. It's just to make a comparison - if you want percent of gross for rent you can multiply by 12.
You can also consider that it's comparing median starting income to average 1 BR rent. One wouldn't expect just starting out that you would have an average single bedroom.
You can also consider that it's comparing median starting income to average 1 BR rent. One wouldn't expect just starting out that you would have an average single bedroom.