Year Percent of GDP (Units) 1999 4.727 2000 3.120 2001 2.690 2002 3.427 2003 3.332 2004 4.080 2005 4.482 2006 5.052 2007 8.892 2008 8.949 2009 21.136 2010 18.799 2011 20.862 2012 20.657 2013 15.611 2014 13.819 2015 16.104 2016 19.267 2017 21.864 2018 21.329 2019 26.801 2020 41.086 2021 35.885 2022 31.082 2023 30.858 2024 30.271 2025 30.319 2026 30.096 2027 29.746 2028 29.301 2029 28.796