This is a major missing feature!
There is no such information like the actual size in % which is absolutely annoying!
The transform studio only shows the W and H so you have to do the math to scale a picture for example to 75%. if you want to fill a frame with a picture at 100%, you have to first set at the Picture frame properties "None - the picture will not be scaled" then place the image so it fills at 100%. Now you can use "doubleclick+select little black arrow" to select the Picture and use the transform studio to scale it - you can use % at the W or H field, so 75% for example. If you change your mind because you want the picture to be at 80% you have to do some math again. So scale it up to 133.33333333333% (since the actual size is set to 100% again) an then scale it again down to 80%.
I am using a lot of objects that have to be exactly at certain scales, floor plans PDF files. So when I come back to any project and open the publisher file after a while, there is no way for me to find out the scale of the floor plans without checking the original PDF sizes at the resource manager and do the math again which is ridiculous!
So once again: PLEASE put the absolute %W and %H into the Transform Studio.