| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $20,099 | $14,514 | 
| 2016 | $20,467 | $14,494 | 
| 2017 | $21,129 | $15,250 | 
| 2018 | $21,129 | $15,468 | 
| 2019 | $22,813 | $16,431 | 
| 2020 | $23,059 | $16,677 | 
| 2021* | $23,481 | $16,927 | 
| 2022* | $23,911 | $17,181 | 
| 2023* | $24,348 | $17,439 | 
| 2024* | $24,794 | $17,700 | 
| 2025* | $25,248 | $17,966 |