Year Percent 1990 1.746 1991 1.75 1992 0.974 1993 0.54 1994 0.69 1995 0.93 1996 0.58 1997 0.82 1998 0.97 1999 0.67 2000 0.51 2001 0.4 2002 0.35 2003 0.7 2004 0.77 2005 0.9 2006 0.68 2007 0.98 2008 0.94 2009 0.92 2010 1.07 2011 1.17 2012 1.14 2013 1.05 2014 1.22 2015 1.56 2016 1.97 2017 2.024 2018 2.078 2019 2.133 2020 2.187 2021 2.241 2022 2.295 2023 2.349 2024 2.404 2025 2.458 2026 2.512 2027 2.566 2028 2.621 2029 2.675 2030 2.729