Google Books Ngram Viewer

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

Ngrams not found: I believe it's, [I believe it's], I think it's, [I think it's]

Search in Google Books:

1900 - 1906 1907 - 1914 1915 - 1943 1944 - 1990 1991 - 2000 i believe it is English
1900 - 1907 1908 - 1925 1926 - 1934 1935 - 1985 1986 - 2000 i think it is English

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