Year	mm Hg
1980	135.3
1981	135
1982	134.6
1983	134.2
1984	133.9
1985	133.5
1986	133.3
1987	133
1988	132.8
1989	132.6
1990	132.5
1991	132.3
1992	132.1
1993	131.9
1994	131.6
1995	131.3
1996	130.9
1997	130.5
1998	130
1999	129.5
2000	129.1
2001	128.5
2002	128
2003	127.5
2004	126.9
2005	126.4
2006	125.9
2007	125.4
2008	124.9