Year annual % 1970 39.565217391304344 1971 42.679127725856695 1972 44.32314410480349 1973 49.47049924357035 1974 47.26720647773279 1975 37.25085910652921 1976 31.196795192789185 1977 19.50381679389313 1978 21.622484829128076 1979 36.97478991596639 1980 48.99597392638037 1981 26.34376572224874 1982 14.072046253323922 1983 32.16048996937692 1984 22.644887150490785 1985 29.06152575048196 1986 19.47657645046417 1987 22.78931369152018 1988 24.31948101063288 1989 38.167322659602846 1990 44.55742852449077 1991 17.525936253346377 1992 19.622180685358256 1993 20.056501883396113 1994 20.202272616841242 1995 27.523719877343833 1996 27.080682337917573 1997 25.25487205618766 1998 62.762870408302604 1999 12.233315504843405 2000 16.62313053743379 2001 11.870838396711235 2002 4.757902316427295 2003 7.937719863839658 2004 9.143972512954848 2005 16.335163913309852 2006 14.943188750137992 2007 19.32512102065858 2008 14.922867328660683 2009 12.95179644135267 2010 15.402287770881854 2011 16.42978384590038 2012 14.954992482017632 2013 12.779697944543278 2014 11.879519361847219 2015 8.996990076380424 2016 10.02849882051502 2017 8.275528079246284 2018 6.290289123738285 2019 6.540404881297798 2020 12.53366087200204 2021 13.966435466597172 2022 8.354912554244038 2023 3.500327528565799