Year	Head
1977	45,000
1978	45,000
1979	63,000
1980	97,300
1981	66,000
1982	85,200
1983	79,700
1984	119,500
1985	124,500
1986	154,400
1987	187,300
1988	226,400
1989	225,700
1990	229,600
1991	208,100
1992	235,000
1993	313,500
1994	344,900
1995	326,122
1996	394,129
1997	394,297
1998	445,723
1999	492,591
2000	548,736
2001	559,823
2001	559,823
2002	594,749
2003	634,499
2004	611,754
2005	556,208
2006	581,743
2007	637,900