Year Percent 1990 1.477 1991 1.488 1992 1.461 1993 1.477 1994 1.524 1995 1.527 1996 1.505 1997 1.41 1998 1.376 1999 1.401 2000 1.328 2001 1.299 2002 1.401 2003 1.56 2004 1.639 2005 1.688 2006 1.698 2007 1.711 2008 1.635 2009 1.638 2010 1.72 2011 2.06 2012 2.147 2013 2.368 2014 2.597 2015 2.636 2016 2.734 2017 2.825 2018 2.916 2019 3.006 2020 3.097 2021 3.188 2022 3.279 2023 3.37 2024 3.46 2025 3.551 2026 3.642 2027 3.733 2028 3.823 2029 3.914 2030 4.005