Google Books Ngram Viewer

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

1800 - 1910 1911 - 1975 1976 - 1983 1984 - 1991 1992 - 2000 headquarters is English
1800 - 1883 1884 - 1915 1916 - 1925 1926 - 1985 1986 - 2000 headquarters are English
1800 - 1914 1915 - 1962 1963 - 1969 1970 - 1987 1988 - 2000 a headquarters English

Run your own experiment! Raw data is available for download here.
© 2013 Google - Privacy & Terms - About Google - About Google Books - About Ngram Viewer