| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $18,455 | $11,788 | 
| 2016 | $18,871 | $11,842 | 
| 2017 | $19,003 | $11,299 | 
| 2018 | $19,003 | $11,581 | 
| 2019 | $19,424 | $10,740 | 
| 2020 | $19,920 | $11,236 | 
| 2021* | $20,362 | $11,288 | 
| 2022* | $20,814 | $11,340 | 
| 2023* | $21,276 | $11,392 | 
| 2024* | $21,749 | $11,444 | 
| 2025* | $22,231 | $11,497 |