| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $24,054 | $17,245 | 
| 2016 | $24,361 | $17,471 | 
| 2017 | $24,569 | $17,784 | 
| 2018 | $24,569 | $18,027 | 
| 2019 | $25,187 | $17,776 | 
| 2020 | $27,021 | $19,610 | 
| 2021* | $27,367 | $19,879 | 
| 2022* | $27,717 | $20,151 | 
| 2023* | $28,072 | $20,427 | 
| 2024* | $28,431 | $20,707 | 
| 2025* | $28,795 | $20,991 |