Year	mm Hg
1980	133.8
1981	133.7
1982	133.5
1983	133.3
1984	133.1
1985	133
1986	132.9
1987	132.8
1988	132.9
1989	132.9
1990	132.9
1991	133
1992	133
1993	133
1994	133
1995	133
1996	132.9
1997	132.9
1998	132.9
1999	132.9
2000	132.9
2001	133
2002	133.2
2003	133.3
2004	133.5
2005	133.7
2006	134
2007	134.2
2008	134.4