Year            Count     Valid     Min        Max        Mean       Stdev      Median
2007            4230      4141      17.160032  21.074646  18.908718  0.881576   19.026613 
2008            4230      4141      15.197839  19.58971   17.264857  0.939246   17.364225 
2009            4230      4141      15.785355  19.123032  17.369863  0.732716   17.396    
2010            4230      4141      15.260549  18.413033  16.736695  0.652885   16.776291 
2011            4230      4141      16.397678  19.663872  17.849967  0.700251   17.876839 
2012            4230      4141      17.349291  19.642033  18.261798  0.420703   18.21542  
2013            4230      4141      16.813644  19.518064  17.936592  0.570518   17.941225 
2014            4230      4141      15.300775  18.555033  16.668363  0.665397   16.651129 
2015            4230      4141      18.116581  19.705549  18.774611  0.358029   18.677387 
2016            4230      4141      16.87487   20.151419  18.159051  0.680474   18.144386 
2017            4230      4141      15.913451  19.540871  17.274836  0.721908   17.228161 
2018            4230      4141      14.840096  18.032806  16.170868  0.632037   16.146936 
2019            4230      4141      15.419484  19.001516  17.086744  0.774136   17.101097 
2020            4230      4141      14.513774  17.76429   16.040189  0.636434   16.054258 
2021            4230      4141      17.720161  19.37113   18.478285  0.340684   18.487    
2022            4230      4141      15.61471   18.206194  16.675742  0.513478   16.643709 
2023            4230      4141      14.492634  18.132967  15.971804  0.740708   15.9629