Year	Number
1992	168.82573690839715
1993	168.14802754904053
1994	170.07207510484062
1995	165.43687767819114
1996	161.82292630168175
1997	157.41761048318028
1998	155.7271153618761
1999	152.81662455900053
2000	152.10005735928297
2001	154.88964575157874
2002	156.47556183886527
2003	156.359987807563
2004	153.70491937046745
2005	154.65858509716523
2006	155.25849878524855
2007	158.0181585592838
2008	173.57025690474038