Year	mm Hg
1980	128
1981	127.8
1982	127.6
1983	127.4
1984	127.3
1985	127.1
1986	126.9
1987	126.7
1988	126.5
1989	126.3
1990	126.2
1991	126.1
1992	126
1993	125.9
1994	125.9
1995	125.8
1996	125.8
1997	125.8
1998	125.7
1999	125.7
2000	125.6
2001	125.6
2002	125.5
2003	125.5
2004	125.4
2005	125.4
2006	125.3
2007	125.3
2008	125.2