Year Number 1996 3.80434775352478 1998 6.52173900604248 2000 10.3260869979858 2002 14.0540542602539 2003 18.9189186096191 2004 18.4079608917236 2005 22.0588226318359 2006 21.5686283111572 2007 22.3300971984863 2008 27.6699028015137 2009 30.1435413360596 2010 27.2727279663086 2011 27.962085723877 2012 23.6966819763184 2013 24.6445503234863 2014 30.769229888916 2015 27.1428565979004 2016 25.238094329834 2017 26.1904754638672 2018 28.0952377319336 2019 30.4761905670166 2020 25.7142848968506 2021 35.238094329834 2022 32.5471687316895