Google Books Ngram Viewer

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

1800 - 1980 1981 - 2002 2003 - 2004 2005 - 2006 2007 - 2008 superheroes English

Run your own experiment! Raw data is available for download here.
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