Google Books Ngram Viewer

Graph these comma-separated phrases:
case-insensitive
between and from the corpus with smoothing of .  
Search in Google Books:

1960 - 1963 1964 - 1975 1976 - 1979 1980 - 2001 2002 - 2008 over a period of centuries English
1960 - 1965 1966 - 1995 1996 - 1999 2000 - 2003 2004 - 2008 over a period of decades English
1960 - 1963 1964 - 1967 1968 - 1970 1971 - 2000 2001 - 2008 a period of two centuries English
1960 - 1964 1965 - 1993 1994 - 1997 1998 - 2002 2003 - 2008 a period of three decades English

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