Year	mm Hg
1980	131.1
1981	130.9
1982	130.6
1983	130.3
1984	129.9
1985	129.5
1986	129.2
1987	128.8
1988	128.5
1989	128.3
1990	128.2
1991	128
1992	127.9
1993	127.8
1994	127.6
1995	127.5
1996	127.4
1997	127.4
1998	127.5
1999	127.6
2000	127.8
2001	128
2002	128.2
2003	128.5
2004	128.8
2005	129.2
2006	129.5
2007	130
2008	130.4