I have managed to obtain the SVG graph from google spreadsheet using developer tools.
What I did
First I ran this command in console:
I clicked on the output blue square which opened the node in the main HTML inspector:
Finally, I copied the outer HTML:
I'm mentioning this for googlers and anyone who'd like to reproduce my steps.
What I don't like
The image is a little bit malformed when opened it in inkscape:
All I need to do to fix that is to cut the rectangles along the most bottom guideline:
How would I do that?