Year	Number of
1967	161100
1968	161700
1969	162300
1970	163900
1971	165200
1972	166800
1973	168900
1974	171100
1975	173200
1976	173900
1977	174800
1978	175200
1979	175700
1980	176000
1981	176200
1982	177500
1983	178200
1984	179900
1985	182200
1986	184600
1987	187800
1988	191200
1989	195500
1990	200700
1991	205900
1992	211900
1993	217600
1994	223300
1995	228900
1996	233000
1997	236900
1998	240100
1999	242400
2000	243800
2001	244300
2002	244800
2003	245200
2004	244700
2005	244300
2006	242700
2007	242100
2008	241200
2009	241100
2010	241100
2011	241200
2012	240800
2013	241600
2014	241000
2015	240100