Year	mm Hg
1980	129.6
1981	129.5
1982	129.3
1983	129.1
1984	128.9
1985	128.7
1986	128.4
1987	128.2
1988	128.1
1989	127.9
1990	127.8
1991	127.7
1992	127.6
1993	127.6
1994	127.6
1995	127.5
1996	127.6
1997	127.6
1998	127.6
1999	127.7
2000	127.7
2001	127.8
2002	127.8
2003	127.9
2004	127.9
2005	128
2006	128.2
2007	128.3
2008	128.5