Google Books Ngram Viewer

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

1900 - 1962 1963 - 1992 1993 - 1995 1996 - 1998 1999 - 2000 conspiracy theory English
1900 - 1975 1976 - 1996 1997 1998 1999 - 2000 conspiracy theories English
1900 - 1978 1979 - 1997 1998 1999 2000 conspiracy theorist English

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