Year annual % 1961 0.515650334937277 1962 1.5986814468074186 1963 2.549326392673663 1964 2.46556985532726 1965 2.4578117140426627 1966 2.670676715840983 1967 2.55379161450972 1968 2.5686086352461217 1969 2.6295767453361947 1970 2.6222362422060996 1971 2.6011885153736074 1972 2.4266605187054324 1973 2.3178759565726494 1974 2.1808032397272967 1975 2.0043809060949656 1976 1.8751038984890158 1977 1.7592390625317478 1978 1.7394607674743838 1979 1.7332209200189368 1980 1.6833546669475083 1981 1.7148365806221193 1982 1.8106782964690638 1983 1.7713659085278408 1984 1.6903385699063875 1985 1.693284216098661 1986 1.749507928861064 1987 1.79928058018821 1988 1.7782300772428101 1989 1.6963484918758809 1990 1.6659267476792081 1991 1.5768436837701358 1992 1.4322982830031918 1993 1.327505796410989 1994 1.2799454212256904 1995 1.2409871163314534 1996 1.2172604184019065 1997 1.1907274928882714 1998 1.1355836147962464 1999 1.0651636579258223 2000 1.0153014490341405 2001 0.9736200693553769 2002 0.9120435761426222 2003 0.8719458932866502 2004 0.8658985106257688 2005 0.8581251806778312 2006 0.811990009935414 2007 0.7586535748634731 2008 0.8020751760301863 2009 0.8146669642139273 2010 0.7917904639802771 2011 0.8293510413478486 2012 0.909504727453438 2013 0.9217158864037032 2014 0.8942556198844613 2015 0.8728643020425864 2016 0.8223663073198679 2017 0.8084877597985809 2018 0.7509400124858985 2019 0.6745006718124671 2020 0.5481771973380773 2021 0.413227733962259 2022 0.13621802515559978 2023 0.2617800998560398