Year            Count     Valid     Min        Max        Mean       Stdev      Median
2007            598       592       19.570612  20.483904  20.078709  0.269355   20.113646 
2008            598       592       19.129614  19.491323  19.259841  0.109066   19.226258 
2009            598       592       19.521774  20.211323  19.862991  0.212131   19.812129 
2010            598       592       16.764904  17.709194  17.280501  0.290982   17.269516 
2011            598       592       19.732128  20.350065  19.992322  0.166448   19.9455   
2012            598       592       19.824451  20.019323  19.913695  0.057634   19.904871 
2013            598       592       18.427355  19.147032  18.916854  0.204125   19.024081 
2014            598       592       15.915387  16.829903  16.3249    0.205577   16.296    
2015            598       592       18.24987   19.280451  18.829729  0.322045   18.890065 
2016            598       592       20.011032  20.467419  20.196839  0.119238   20.164388 
2017            598       592       20.204161  21.371807  20.822322  0.343534   20.815081 
2018            598       592       20.163065  20.724903  20.46698   0.180645   20.521257 
2019            598       592       18.839613  19.782322  19.401976  0.262422   19.462646 
2020            598       592       20.178419  20.560387  20.327009  0.098087   20.299888 
2021            598       592       17.79887   18.791323  18.124011  0.221437   18.078435 
2022            598       592       16.084644  17.359291  16.798668  0.341317   16.840484 
2023            598       592       21.009258  21.364935  21.129099  0.075505   21.110387