Google Books Ngram Viewer

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

1800 - 1976 1977 - 1995 1996 - 1997 1998 - 1999 2000 key issue English
1800 - 1973 1974 - 1993 1994 - 1995 1996 - 1997 1998 - 2000 key decision English
1800 - 1972 1973 - 1994 1995 - 1996 1997 - 1998 1999 - 2000 key role English
1800 - 1976 1977 - 1994 1995 - 1996 1997 - 1998 1999 - 2000 key element English
1800 - 1969 1970 - 1994 1995 - 1996 1997 - 1998 1999 - 2000 key factor English

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