What calendar dates starting from 1960 was Mother's Day celebrated?

Mother's Day calendar 1960 through 2009 is as follows (not UK):

1960 - May 8

1961 - May 14

1962 - May 13

1963 - May 12

1964 - May 10

1965 - May 9

1966 - May 8

1967 - May 14

1968 - May 12

1969 - May 11

1970 - May 10

1971 - May 9

1972 - May 14

1973 - May 13

1974 - May 12

1975 - May 11

1976 - May 9

1977 - May 8

1978 - May 14

1979 - May 13

1980 - May 11

1981 - May 10

1982 - May 9

1983 - May 8

1984 - May 13

1985 - May 12

1986 - May 11

1987 - May 10

1988 - May 8

1989 - May 14

1990 - May 13

1991 - May 12

1992 - May 10

1993 - May 9

1994 - May 8

1995 - May 14

1996 - May 12

1997 - May 11

1998 - May 10

1999 - May 9

2000 - May 14

2001 - May 13

2002 - May 12

2003 - May 11

2004 - May 9

2005 - May 8

2006 - May 14

2007 - May 13

2008 - May 11

2009 - May 10