DateString values in xAxis are more than the entries count

I used dateFormatter from the demo. I pass a timestamp in the stringForValue method and convert it to string.
When I run the application strings are more than my values. Formatter is called more than my data counts.
For example I have 1/4, 3/4 and 10/4. My graph has values from the 1/4 until I don't know because my screen does not fits the graph.

What can I do to have only my entries dates and what can I do to fits the graph in my screen?

Thank you