We just started getting this issue within the last week, and it has gotten progressively worse:
The steering feels like there is no power boost at all - my wife can't drive it, and I took it to work today to verify her complaint. I checked the power steering fluid reservoir and it has fluid showing on the dipstick, so no major leaks. I don't hear any belt squealing, so assume the pump is functioning. I haven't gotten underneath to check the rack yet. Any ideas what to check?

 

I had similar issue on my 04, turned out I needed to grease my ( I forget what its called) but its the transition from the steering column to the rack and pinion. Its under the hood, right where the steering column comes out, you can hit it with WD-40, from the top, if that fixes the issue then you can get some grease do a better job.