Find the total health care expenditures in year $\"\"$ is $\"\"$ .

The percentage of income spent on health care in year $\"\"$ is $\"\"$ .

Total income in year $\"\"$ is $\"\"$ .

Total health care expenditures in year $\"\"$ ( $\"\"$ ) is equals to the total income in year $\"\"$ ( $\"\"$ ) multiplies the percentage of income spent on health care in year $\"\"$ ( $\"\"$ ).

Thus, $\"\"$ .

The function is $\"\"$ .