Year Number 1960 0 1965 0 1970 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 1027 1993 3800 1994 8364 1995 15003 1996 28500 1997 77100 1998 167460 1999 274344 2000 401272 2001 656835 2002 917196 2003 1219550 2004 1536712 2005 1871602 2006 2183696 2007 2217008 2008 2298610 2009 2303600 2010 2306100 2011 2309000 2012 2630873 2013 2558000 2014 2384000 2015 2590000 2016 2650273 2017 2464122 2018 2070180 2019 2071652 2020 2051359 2021 2161725 2022 2167034