In what year became john major the leader of the conservative party?

Sir John Major, KG, CH is a British politician who was the Prime Minister of the United Kingdom and the Leader of the Conservative Party from 1990 to 1997. He served as Foreign Secretary and then Chancellor of the Exchequer in the Thatcher Government from 1989 to 1990, and was the Member of Parliament for Huntingdon from 1979 to 2001. He is the oldest living former Prime Minister.

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Identify the best use of this document for a historian.  

answer :To understand the conditions child laborers experienced