| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $23,565 | $17,781 | 
| 2016 | $23,629 | $17,053 | 
| 2017 | $24,231 | $18,777 | 
| 2018 | $24,231 | $18,584 | 
| 2019 | $24,586 | $19,306 | 
| 2020 | $24,230 | $18,950 | 
| 2021* | $24,295 | $18,755 | 
| 2022* | $24,361 | $18,562 | 
| 2023* | $24,427 | $18,370 | 
| 2024* | $24,493 | $18,181 | 
| 2025* | $24,559 | $17,994 |