Mr$.$ Hugh Warner is a very cautious businessman. His supplier offers trade credit terms of $2/12,$ net $75.$ Mr$.$ Warner never takes the discount offered, but he pays his suppliers in $65$ days rather than the $75$ days allowed so that he is sure the payments are never late.

What is Mr$.$ Warner's cost of not taking the cash discount?

Note: Use a $360-$day year. Do not round intermediate calculations. Input your answer as a percent rounded to $2$ decimal places.$)$