Google Books Ngram Viewer

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

1800 - 1945 1946 - 1997 1998 - 2001 2002 - 2004 2005 - 2008 klassenkamerad German
1800 - 1819 1820 - 1977 1978 - 1988 1989 - 1998 1999 - 2008 schulfreund German

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