Year	mm Hg
1980	136
1981	135.7
1982	135.4
1983	135.1
1984	134.7
1985	134.4
1986	134
1987	133.7
1988	133.3
1989	132.9
1990	132.5
1991	132
1992	131.4
1993	130.9
1994	130.4
1995	129.9
1996	129.5
1997	129
1998	128.6
1999	128.2
2000	127.9
2001	127.5
2002	127.2
2003	126.9
2004	126.7
2005	126.4
2006	126.2
2007	125.9
2008	125.7