Google Books Ngram Viewer

Graph these comma-separated phrases:
case-insensitive
between and from the corpus with smoothing of .  
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1900 - 1914 1915 - 1947 1948 1949 - 1968 1969 - 2008 minor metals English
1900 - 1933 1934 - 1960 1961 1962 - 2003 2004 - 2008 rare earth metals English
1900 - 1943 1944 - 1950 1951 1952 - 1985 1986 - 1992 strategic metals English

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