I also have the same question. I have found something that might work to get the data you are looking for. This method works, but I feel like there is or should be an easier way to do this.
Select the object or NURBs curve, etc from which you want the attribute data.
File>Export selection (click on the open square to get options)
Within the Export selection options
-General options> File type> move (This is not a movie file although my PC interprets it that way.)
-File type specific options- click on "from channel box" and select the attributes that you want to get the data for from the channel box.
Name the file and export it.
Here's a link to a URL where I found this information on Andrew Hazelden's Blog:
As I mentioned, my computer thinks this is a movie file, which it isn't. Change the file extension to .xls or .csv to get comma separated values. Open it with Excel or a similar software.
The downside to this data is that there is no indication which frames are actually keyframes, so it involves more work to get the information you're seeking.
Hopefully you found an answer long before now since your post is more than 1 year old. If not, I hope this work around is helpful. If you found a better to do this, I'd love to hear how you do it.