| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $16,694 | $12,518 | 
| 2016 | $17,429 | $12,984 | 
| 2017 | $18,398 | $14,055 | 
| 2018 | $18,398 | $13,633 | 
| 2019 | $19,755 | $14,434 | 
| 2020 | $20,350 | $15,029 | 
| 2021* | $21,245 | $15,648 | 
| 2022* | $22,180 | $16,293 | 
| 2023* | $23,156 | $16,964 | 
| 2024* | $24,175 | $17,663 | 
| 2025* | $25,239 | $18,391 |