Missing digits on y-axis labels

If you look here you'll see that all y-axis tick labels are `1`:
http://www.astropy.org/astropy-benchmarks/#time_coordinates.FrameBenchmarks.time_init_array
(also see attached screenshot)

I guess the bug is that more digits should be printed?

![screen shot 2014-12-01 at 14 18 25](https://cloud.githubusercontent.com/assets/852409/5246144/1e8e9cb0-7965-11e4-83d2-4d352906e738.png)