Year	mm Hg
1980	133.6
1981	133.6
1982	133.5
1983	133.4
1984	133.2
1985	133.1
1986	133
1987	132.9
1988	132.9
1989	132.8
1990	132.8
1991	132.7
1992	132.6
1993	132.5
1994	132.4
1995	132.4
1996	132.3
1997	132.3
1998	132.3
1999	132.3
2000	132.4
2001	132.5
2002	132.7
2003	132.9
2004	133.1
2005	133.4
2006	133.6
2007	133.9
2008	134.1