| Year | Total Expenses | Average Net Price | 
|---|---|---|
| 2015 | $23,680 | $13,283 | 
| 2016 | $23,940 | $13,186 | 
| 2017 | $24,280 | $13,831 | 
| 2018 | $24,280 | $13,622 | 
| 2019 | $24,962 | $13,312 | 
| 2020 | $25,000 | $13,350 | 
| 2021* | $25,275 | $13,253 | 
| 2022* | $25,553 | $13,156 | 
| 2023* | $25,834 | $13,060 | 
| 2024* | $26,118 | $12,964 | 
| 2025* | $26,406 | $12,870 |