Dory took out an interest$-$only mortgage to buy a retail mall whose net operating income equals $$2\mathrm{.}98$ million per year.

Terms of the mortgage are as follows:

loan amount: $$22$ million

interest rate: $9\%$ per year

term: $17$ years

balloon: $5$ years.

The debt service coverage ratio $($DSCR$)$ of this mortgage equals $\_\_\_\_$