Year % 2006 3.79492045431925 2007 3.81390595309035 2008 3.61200383000281 2009 4.58153542349424 2010 5.09505050694966 2011 4.98718024999289 2012 5.12553014876497 2013 5.36846249339605 2014 5.21248631883844 2015 5.37707549029426 2016 6.19177596311036 2017 6.89234780812498 2018 6.87103074202291 2019 7.50821379217828 2020 7.26713946592396