Google Books Ngram Viewer

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

1500 - 1966 1967 - 1969 1970 - 1985 1986 - 2005 2006 - 2008 ombudsman English

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