Year Percent 1990 2.434 1991 2.584 1992 2.78 1993 3.116 1994 3.832 1995 4.261 1996 4.65 1997 4.742 1998 4.787 1999 4.754 2000 4.47 2001 4.096 2002 3.887 2003 3.58 2004 3.246 2005 3.161 2006 2.981 2007 2.807 2008 2.751 2009 3.085 2010 2.982 2011 2.859 2012 2.849 2013 2.845 2014 2.869 2015 3.092 2016 3.028 2017 2.946 2018 2.864 2019 2.782 2020 2.7 2021 2.619 2022 2.537 2023 2.455 2024 2.373 2025 2.291 2026 2.209 2027 2.127 2028 2.045 2029 1.963 2030 1.881