| Year | Total |
| 1974 | 3,189 |
| 1975 | 3,179 |
| 1976 | 2,433 |
| 1977 | 1,700 |
| 1978 | 1,234 |
| 1979 | 1,665 |
| 1980 | 1,772 |
| 1981 | 2,344 |
| 1982 | 2,286 |
| 1983 | 2,516 |
| 1984 | 2,365 |
| 1985 | 2,474 |
| 1986 | 2,545 |
| 1987 | 2,299 |
| 1988 | 2,162 |
| 1989 | 2,388 |
| 1990 | 2,390 |
| 1991 | 2,186 |
| 1992 | 2,257 |
| 1993 | 3,276 |
| 1994 | 3,312 |
| 1995 | 2,987 |
| 1996 | 3,086 |
| 1997 | 3,057 |
| 1998 | 3,555 |
| 1999 | 3,561 |
| 2000 | 4,390 |
| 2001 | 4,476 |
| 2002 | 4,371 |
| 2003 | 4,310 |
| 2004 | 3,746 |
| 2005 | 3,685 |
| 2006 | 3,339 |
| 2007 | 3,600 |
| 2008 | 3,377 |
| 2009 | 3,450 |
| 2010 | 3,427 |
| 2011 | 3,868 |