Google Books Ngram Viewer

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

1960 - 1967 1968 - 1976 1977 - 1979 1980 - 2001 2002 - 2008 working mother English
1960 - 1992 1993 - 2005 2006 2007 2008 working mom English

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