Year Percent of GDP (Units) 1997 8.723 1998 18.141 1999 26.058 2000 27.339 2001 32.763 2002 37.187 2003 43.711 2004 46.791 2005 45.848 2006 44.481 2007 42.396 2008 44.255 2009 41.364 2010 39.009 2011 35.972 2012 37.640 2013 33.452 2014 35.053 2015 33.957 2016 29.349 2017 26.628 2018 24.754 2019 25.224 2020 21.762 2021 20.142 2022 19.397 2023 17.655 2024 17.282 2025 17.811 2026 18.302 2027 19.128 2028 20.253 2029 21.567