Year	mm Hg
1980	134.5
1981	134.3
1982	134.1
1983	134
1984	133.8
1985	133.6
1986	133.4
1987	133.3
1988	133.1
1989	133
1990	132.9
1991	132.7
1992	132.6
1993	132.5
1994	132.4
1995	132.3
1996	132.3
1997	132.2
1998	132.2
1999	132.2
2000	132.3
2001	132.5
2002	132.7
2003	133
2004	133.3
2005	133.7
2006	134.1
2007	134.5
2008	134.9