Impress: scale (resize) an object by percentage?

In Impress, is there a way to scale (resize) an object (not an image) by percentage?
I’m using LibreOffice on Windows 7 (English).

As I never work with percentage to change the size of an object I made a test and found it is not possible.

Is changing by percentage a really important or needed feature? I personally don’t need this feature as I can make size adjustment better using normal length units like millimeter or centimeter. Length units also can be compared with the ruler at the top and left side of a slide.

However, if you feel this an important feature, please feel free to file an enhancement request here: