Year annual % 1961 5.59430751417022 1962 5.568733579754582 1963 5.536256916603045 1964 5.528652477361164 1965 5.52778430678751 1966 5.548155803858096 1967 5.56391434791234 1968 5.550070209193018 1969 5.510839621540444 1970 5.490103589727566 1971 5.323996375039026 1972 5.304912822754287 1973 5.266574494251819 1974 5.176142456752841 1975 5.010644357393968 1976 4.601124739158651 1977 3.4251785321967745 1978 3.326379647702192 1979 3.380112336811134 1980 3.463184542094846 1981 3.546421601258303 1982 3.612106191616525 1983 3.6558075416096356 1984 3.6859790954391056 1985 3.73999364469995 1986 3.8289789289751104 1987 3.871935348787767 1988 3.796383076302598 1989 3.2517937554925282 1990 3.24627523789646 1991 3.21984231490932 1992 3.1635723546398395 1993 3.1054987935615475 1994 3.0169829647083932 1995 2.8893776247158547 1996 2.7722797714995537 1997 2.68267728392177 1998 2.6512420936782393 1999 2.6729773346672316 2000 2.708788316465087 2001 2.736564546910759 2002 2.7677564938443613 2003 3.174036076992385 2004 3.4930031844201506 2005 3.5241710163463535 2006 3.58041901367083 2007 3.6037830682049083 2008 3.6014940317699704 2009 3.631500710591544 2010 3.6609864276196795 2011 3.665643914101355 2012 3.6617480147883277 2013 3.6401797851329873 2014 3.641058380116588 2015 3.657856948873587 2016 3.657309854479153 2017 3.672444682636066 2018 3.677054615010243 2019 3.6697497317509513 2020 3.663774876412039 2021 3.6337850929241577 2022 3.567200425910424 2023 3.546352038674981