Year	mm Hg
1980	128.9
1981	128.8
1982	128.6
1983	128.4
1984	128.2
1985	128.1
1986	128
1987	127.9
1988	127.8
1989	127.8
1990	127.9
1991	128
1992	128
1993	128.1
1994	128.1
1995	128.2
1996	128.4
1997	128.5
1998	128.6
1999	128.7
2000	128.8
2001	128.9
2002	129
2003	129.2
2004	129.3
2005	129.4
2006	129.5
2007	129.5
2008	129.6