GNUplot--Change steps of yrange

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http://unix.stackexchange.com – I'm learning GNUplot. I need to change steps in which Y values increase while plotting my graph.xrange command will change range but steps. Ex. I have data like this 1 1000 2 1500 3 1 4 200 ... By default GNUplot is taking Y range as[0,5000] which is OK for me. but y values are increasing in steps of 500, I want to increase in steps of 200. Is it possible? (HowTos)