Year	mm Hg
1980	134.3
1981	134.1
1982	133.8
1983	133.6
1984	133.4
1985	133.2
1986	133
1987	133
1988	132.9
1989	132.8
1990	132.8
1991	132.6
1992	132.5
1993	132.4
1994	132.2
1995	132
1996	131.8
1997	131.6
1998	131.3
1999	131
2000	130.6
2001	130.2
2002	129.8
2003	129.3
2004	128.9
2005	128.5
2006	128
2007	127.6
2008	127.2