| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $20,294 | $13,760 | 
| 2016 | $20,640 | $13,158 | 
| 2017 | $21,300 | $14,725 | 
| 2018 | $21,300 | $14,307 | 
| 2019 | $21,820 | $13,116 | 
| 2020 | $21,820 | $13,116 | 
| 2021* | $22,191 | $12,744 | 
| 2022* | $22,568 | $12,382 | 
| 2023* | $22,952 | $12,030 | 
| 2024* | $23,342 | $11,688 | 
| 2025* | $23,739 | $11,356 |