Year No_publications_2_author_names No_publications_3_author_names 1961 5 1 1962 10 0 1963 4 0 1964 5 0 1965 3 0 1966 6 0 1967 4 0 1968 5 0 1969 5 1 1970 12 0 1971 9 0 1972 9 1 1973 10 1 1974 11 0 1975 1 1 1976 2 1 1977 15 1 1978 15 0 1979 11 1 1980 9 0 1981 15 0 1982 19 0 1983 11 0 1984 15 1 1985 15 0 1986 23 0 1987 12 1 1988 22 0 1989 15 1 1990 17 1 1991 10 2 1992 25 3 1993 14 2 1994 24 2 1995 15 1 1996 11 3 1997 17 3 1998 18 3 1999 26 4 2000 26 3 2001 21 3 2002 17 2 2003 22 2 2004 19 4 2005 15 5 2006 27 4 2007 26 4 2008 19 5 2009 29 9 2010 30 8