Year Percent change (Units) 2003 6.530 2004 13.266 2005 10.562 2006 4.285 2007 16.092 2008 18.814 2009 -9.836 2010 10.246 2011 9.312 2012 5.875 2013 7.241 2014 1.487 2015 1.131 2016 4.588 2017 3.041 2018 0.755 2019 2.773 2020 4.987 2021 15.342 2022 1.936