Year annual % 1961 2.48716112748639 1962 2.27728810106676 1963 2.21577882578914 1964 2.14600380568892 1965 2.12711031805335 1966 2.19482078105828 1967 2.2271479736908 1968 2.24398374230985 1969 2.31232882673833 1970 2.36341181456913 1971 2.39199682291101 1972 2.37936889767955 1973 2.32627618285015 1974 2.2633280112203 1975 2.21251749459205 1976 2.17253685235323 1977 2.13867935178094 1978 2.10393134737699 1979 2.0691900659496 1980 2.04624584112729 1981 2.04936800195646 1982 2.06714159406125 1983 2.09255585473102 1984 2.12007026512604 1985 2.14354523380954 1986 2.16168101808063 1987 2.1740062941715 1988 2.17887920258063 1989 2.26940661326066 1990 2.64424606515874 1991 3.20861357357665 1992 3.58442578343694 1993 3.67719965352654 1994 3.66278702808236 1995 3.63389307724082 1996 3.60494215869651 1997 3.58211946279432 1998 3.53309876155072 1999 3.49089390798656 2000 3.4521329401203 2001 3.39455509979259 2002 3.34955956126701 2003 3.31123407239589 2004 3.26552943968256 2005 3.2156031499028 2006 3.17128786595142 2007 3.12366111372057 2008 3.08611399149295 2009 3.0478162226257 2010 3.00352670267458 2011 2.90298961470657 2012 2.77799045268741 2013 2.69288253584226 2014 2.61569523033674 2015 2.54320066295637 2016 2.46859434505795 2017 2.39411255967524 2018 2.325313321969 2019 2.26018781066996 2020 2.14763227357632 2021 2.02856054038959 2022 1.92302821820746 2023 1.82993546980529