Fixed number of Y-axis labels - possible?

The trick is, the graph is working off a dynamic input range, so the data always changes.
It's just a bar graph, with a time series on the X-axis.
I'm using Excel 2010 set to format the Y-axis labels as fully "Auto", which makes sense, as the graph changes size depending on the input range selected.
Using this auto setting, sometimes the graph will have 6 data labels on the Y-axis, sometimes 8.

Is there a way to let Excel continue to set the minimum and maximum points itself, but force it to always show me, say, ten y-axis labels?
I'm suspecting not, but does anyone know for sure?

regards,
Graeme

Thought it might be something like that.
Not for me, I'm afraid.
Thanks anyway,
Graeme