Year            Count     Valid     Min        Max        Mean       Stdev      Median
2007            310       302       18.875935  19.629354  19.214792  0.213552   19.177032 
2008            310       302       18.460451  18.972065  18.700324  0.116858   18.687258 
2009            310       302       19.666677  20.065613  19.885754  0.098568   19.883855 
2010            310       302       15.905581  17.032032  16.399119  0.320572   16.344774 
2011            310       302       18.208645  18.428549  18.32393   0.051301   18.327435 
2012            310       302       17.434807  17.93087   17.700221  0.101061   17.713678 
2013            310       302       18.753967  18.938419  18.838904  0.037789   18.83358  
2014            310       302       16.493645  17.662903  17.203421  0.295061   17.301645 
2015            310       302       18.534452  19.249388  18.83484   0.197111   18.788918 
2016            310       302       16.422678  16.784     16.641102  0.066943   16.642403 
2017            310       302       17.537291  18.156162  17.828136  0.157918   17.85392  
2018            310       302       15.788129  16.327257  16.018816  0.116028   16.001984 
2019            310       302       15.931774  16.727386  16.305429  0.216615   16.272275 
2020            310       302       17.264225  17.849743  17.515492  0.13786    17.494048 
2021            310       302       15.936807  17.125225  16.507294  0.291162   16.487886 
2022            310       302       18.481451  20.017225  19.249798  0.4524     19.213144 
2023            310       302       16.214096  16.64271   16.384431  0.095678   16.369951