Gill pressure 1985 - 985.0 982.2 983.7 - 979.8 971.8 980.6 971.5 972.8 969.4 977.5 1986 985.9 990.7 989.4 978.5 989.8 988.8 977.6 980.6 976.8 970.6 973.5 979.8 1987 990.3 987.3 986.0 987.0 981.5 985.0 990.1 974.3 986.9 976.4 977.4 983.5 1988 986.7 983.8 984.8 981.1 987.8 993.1 974.2 973.1 981.9 986.9 980.5 981.0 1989 982.7 985.4 982.5 985.9 968.8 979.3 - - - - - - 1990 - - - - - - - - - - - - 1991 - 987.2 979.0 982.3 984.1 986.9 988.8 979.6 975.4 975.1 980.9 992.6 1992 987.2 993.4 984.2 982.2 987.3 991.2 978.5 982.4 - - 975.9 980.8 1993 994.3 976.3 983.3 978.1 980.9 974.5 968.6 974.7 - - 977.7 982.6 1994 982.8 981.7 977.1 982.5 982.7 995.8 985.4 - - - - 979.5 1995 979.3 979.4 989.1 980.8 978.8 984.5 999.8 - - - - 975.6 1996 983.5 988.5 983.1 975.2 983.5 978.5 977.9 984.6 984.9 969.0 984.8 983.0 1997 986.8 987.9 977.7 982.6 968.8 983.6 975.7 973.4 977.1 974.4 984.3 989.3 1998 985.2 979.3 979.1 972.8 979.8 973.6 976.8 975.3 985.5 976.9 970.5 981.3 1999 980.7 985.7 983.2 978.8 975.1 997.4 976.0 980.8 977.7 962.5 968.9 973.6 2000 976.6 982.1 981.3 979.4 980.2 982.7 977.5 980.6 985.4 974.7 978.8 995.6 2001 991.1 986.2 982.9 975.8 982.0 978.7 983.5 981.5 974.3 969.0 973.9 975.1 2002 982.3 974.8 987.5 978.0 989.2 992.7 985.8 975.4 983.5 987.8 982.5 977.6 2003 - - - - - - 972.4 - - - - - 2004 - - - - - - - - - - - - 2005 - 974.8 - 974.4 974.4 - 975.6 971.7 - 964.8 975.2 991.4 2006 981.8 - - - - - - - - - - - 2007 - - - 981.3 982.3 981.3 - 974.6 974.0 979.6 979.5 973.2 2008 978.0 978.4 983.4 982.1 979.9 974.0 976.1 980.3 966.7 971.6 - - 2009 - - - - - - - - - - - -