Year annual % 1964 35.4210649777883 1965 -2.72698027762915 1966 15.7801012491141 1967 36.9265248728318 1968 53.3216727107739 1969 6.17619573522314 1970 8.02528404548487 1971 5.77734982596516 1972 15.8042153907951 1973 15.6427621238194 1974 29.4692810459945 1975 28.6579701952268 1976 80.385959075414 1977 68.9477081989997 1978 48.7690376115202 1979 101.051260411497 1980 46.6259068303308 1981 35.4082648744294 1982 36.6996975740914 1983 76.5266976662658 1984 52.2270113573208 1985 23.820784521335 1986 44.4 1987 78.6703601108033 1988 71.0917312661503 1989 104.06522942826 1990 81.295404814004 1991 2154.43682711341 1992 4129.16985661558 1993 1986.90476190476 1994 23773.1317741016 1995 541.908883239027 1996 492.441850235414 1997 198.516707416463 1998 29.1488069236652 1999 284.894975914087 2000 513.906843747535 2001 359.936614264586 2002 31.5225826025495 2003 12.8739657187405 2004 3.99438400815971 2005 21.3168167229341 2006 13.0526949745101 2007 16.945100654195 2008 17.3013845700157 2009 2.79999999999982 2010 7.10000000000037 2011 15.316515913949 2012 9.72182806273364 2013 0.808223101487111 2014 1.24303889760803 2015 0.74419899478147 2016 2.88585107289988