Google Books Ngram Viewer

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

1880 - 1970 1971 - 2002 2003 - 2004 2005 - 2006 2007 - 2008 tornado alley English

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