Year            Count     Valid     Min        Max        Mean       Stdev      Median
2007            553       489       18.421549  18.845322  18.64411   0.101581   18.637581 
2008            553       489       17.603258  17.899065  17.742481  0.069511   17.738741 
2009            553       489       18.034128  18.634418  18.391869  0.12898    18.410742 
2010            553       489       14.909904  15.494097  15.174771  0.154328   15.185387 
2011            553       489       18.797291  19.093096  18.947125  0.061543   18.944065 
2012            553       489       20.131128  20.417355  20.282271  0.071058   20.272871 
2013            553       489       16.212     16.538967  16.392125  0.066397   16.387806 
2014            553       489       16.665581  17.14587   16.891074  0.129242   16.877548 
2015            553       489       17.94087   18.395     18.153222  0.111382   18.136354 
2016            553       489       18.51071   18.816904  18.648362  0.068547   18.641548 
2017            553       489       19.07942   19.495064  19.30619   0.102046   19.303226 
2018            553       489       18.498194  18.856356  18.652681  0.094087   18.624001 
2019            553       489       17.651291  17.97971   17.802596  0.073618   17.811129 
2020            553       489       20.165646  20.563129  20.389216  0.096066   20.395775 
2021            553       489       18.299774  18.570065  18.391848  0.0727     18.363741 
2022            553       489       18.952677  19.168581  19.061447  0.063443   19.071419 
2023            553       489       20.199032  20.772968  20.537047  0.184587   20.612516