Dates are more frequently abbreviated this way, using a dash. Personally, I don't like how it looks when you add the spaces. When you're simply giving the beginning and end dates of something, you normally just do the starting month/year, a dash and the ending month/year.
John Smith, Director of Studies, 1992-1995
Helen Jones, Music Teacher, 2004-2007
Sarah Ryman, Temporary Typist, Mar-Sept 2003
It's the same as birth and death dates:
David Smith, 1954-2009
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