Year	mm Hg
1980	128
1981	128.1
1982	128.1
1983	128.1
1984	128.1
1985	128
1986	128
1987	128
1988	128
1989	128
1990	128
1991	127.9
1992	127.8
1993	127.7
1994	127.5
1995	127.4
1996	127.2
1997	127
1998	126.9
1999	126.7
2000	126.5
2001	126.5
2002	126.4
2003	126.4
2004	126.4
2005	126.4
2006	126.4
2007	126.4
2008	126.4