8. Over a 15 -year period, the average cost of staying in a hospital for 24 hours increased from $\mathrm{\$}300$ to $\mathrm{\$}1323$. Find the percent of increase for the 15 -year period. Round the answer to the nearest whole percent.
441
77
23
341

Step 1 ：Let the initial cost of staying in a hospital for 24 hours be $\mathrm{\$}300$ and the final cost be $\mathrm{\$}1323$.

Step 2 ：The percent increase can be calculated by subtracting the initial value from the final value, dividing the result by the initial value, and then multiplying by 100 to get the percentage.

Step 3 ：Subtract the initial value from the final value: $1323-300=1023$.

Step 4 ：Divide the result by the initial value: $\frac{1023}{300}=3.41$.

Step 5 ：Multiply by 100 to get the percentage: $3.41\times 100=341$.

Step 6 ：Round the result to the nearest whole percent: $\text{round}(341.0)=341$.

Step 7 ：Final Answer: The percent of increase for the 15-year period is $\boxed{{\displaystyle 341}}$.