Year % 1996 38.6042 1999 32.54333 2000 32.65204 2001 33.24416 2002 33.68474 2003 32.82352 2006 32.52663 2007 37.07019 2008 38.66853 2009 35.69657 2010 38.3819 2011 36.40912 2012 29.04075 2013 30.42115 2015 36.06017 2016 35.68402 2017 33.88606 2018 28.23594 2019 23.17581 2020 27.35297 2021 27.29786