| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $23,852 | $16,322 | 
| 2016 | $24,722 | $17,482 | 
| 2017 | $25,929 | $17,802 | 
| 2018 | $25,929 | $17,708 | 
| 2019 | $26,935 | $17,774 | 
| 2020 | $25,466 | $16,305 | 
| 2021* | $26,396 | $16,365 | 
| 2022* | $27,359 | $16,426 | 
| 2023* | $28,358 | $16,487 | 
| 2024* | $29,393 | $16,548 | 
| 2025* | $30,465 | $16,609 |