Year Number 1970 27655.763671875 1971 29140.609375 1972 31374.63671875 1973 30861.337890625 1974 31129.732421875 1975 30539.912109375 1976 30464.98046875 1977 31496.537109375 1978 30709.53125 1979 29552.01953125 1980 30239.880859375 1981 30203.099609375 1982 31117.74609375 1983 33122.12890625 1984 32469.806640625 1985 32426.583984375 1986 32546.4765625 1987 32142.08203125 1988 32663.666015625 1989 33429.4375 1990 32969.41796875 1991 32908.3515625 1992 33408.828125 1993 34409.921875 1994 34311.6484375 1995 34204.953125 1996 34319.3125 1997 34408.27734375 1998 35041.29296875 1999 35929.6328125 2000 36338.12109375 2001 36212.21484375 2002 35898.83203125 2003 36529.5234375 2004 37564.0390625 2005 38002.33984375 2006 39040.4765625 2007 40024.73046875 2008 39556.44140625 2009 40260.265625 2010 40175.24609375 2011 39330.54296875 2012 39269.35546875 2013 39875.33984375 2014 39465.578125 2015 39176.72265625 2016 38919.00390625 2017 38953.46875 2018 37648.28515625 2019 39017.859375 2020 39064.125 2021 38604.27734375 2022 38602.63671875