Google Books Ngram Viewer

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

1900 - 1963 1964 - 2005 2006 2007 2008 best friends forever English
1900 - 1919 1920 - 1936 1937 1938 - 2004 2005 - 2008 good friends forever English

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