Year annual % 1968 14.39594123242786 1969 17.388894021990208 1970 10.735930735930737 1971 13.810505366408416 1972 13.12765425930552 1973 22.93253836811306 1974 7.1717262439374885 1975 19.078147915357217 1976 37.0715743542825 1977 18.897132441660464 1978 16.16141987304055 1979 11.751147790851132 1980 7.832537715606859 1981 19.700755822921487 1982 11.176258343857116 1983 10.982323964068385 1984 20.51906005221932 1985 32.3864571869286 1986 25.38325587484454 1987 28.19345542631612 1988 23.648758715058317 1989 18.335957209951847 1990 4.23024041592679 1991 23.695502986704692 1992 19.46933603321021 1993 65.97370166185115 1994 205.56029743176597 1995 181.699299132101 1996 38.54926736104524 1997 19.04796246915564 1998 38.017058785774424 1999 37.84686747433268 2000 80.54822455745546 2001 28.1621941329841 2002 116.75160125568414 2003 19.87091599412707 2004 32.41350868488978 2005 11.140174030406508 2006 27.14084896607714 2007 28.78554926803333 2008 20.868498171009545 2009 14.887924488206949 2010 10.679443057010014 2011 21.455972153021765 2012 21.139043517435425 2013 11.06773211409679 2014 5.450824246428035 2015 11.754495014081513 2016 52.20754636586331 2017 8.69518164223845 2018 9.064560357578184 2019 5.694463774858549 2020 62.05429954779675 2021 43.90682417239038 2022 46.85485578348647 2023 19.615501357074404