Year	mm per year
1992	447
1993	447
1994	447
1995	447
1996	447
1997	447
1998	447
1999	447
2000	447
2001	447
2002	447
2003	447
2004	447
2005	447
2006	447
2007	447
2008	447
2009	447
2010	447
2011	447
2012	447
2013	447
2014	447
2015	447
2016	447
2017	447
2018	447
2019	447
2020	447