Year annual % 1961 20.274914089347078 1962 17.42857142857143 1963 17.810218978102192 1964 27.98430400660884 1965 50.94400516378893 1966 28.16976694462262 1967 24.46409208441071 1968 26.598311218335347 1969 32.0205388809486 1970 18.84923817161187 1971 45.35946830403832 1972 20.252518219375204 1973 29.85215780128156 1974 56.45446573224929 1975 4.854599519290145 1976 29.856574643701695 1977 25.495381094582903 1978 14.867817529814026 1979 35.86954943443349 1980 26.63189843115462 1981 15.738615265165581 1982 -7.8913915848166 1983 -5.027760478789094 1984 0.1731021969808532 1985 27.047147778523602 1986 -6.396630847222283 1987 2.998794138158647 1988 -4.620286415637823 1989 11.28515906009834 1990 18.98246158250899 1991 -1.087751516986973 1992 16.49380160232908 1993 5.94488188976378 1994 14.000702091439333 1995 9.557130580318319 1996 1.0266723116003387 1997 -3.704091729235784 1998 3.8054712715931487 1999 7.401800374981077 2000 3.1053812874754683 2001 4.315865854812758 2002 6.106154544079843 2003 6.500589062440619 2004 13.76969329312898 2005 29.005951587482066 2006 14.078531485533674 2007 38.04307285727987 2008 49.19214765981427 2009 17.41287868988177 2010 -0.5733348610511285 2011 24.00042816809017 2012 12.582639845252514 2013 6.294448959894339 2014 -0.3387012639388203 2015 12.507044918415398 2016 22.07368060726097 2017 24.747973050113146 2018 -0.6287157264548598 2019 -1.8537374016916488 2020 15.180200941761763 2021 -20.26376795954747