We are discussing this chart: http://i.stack.imgur.com/ecCRG.png
D in 2011 was -5.6 along x D in 2013 is -4.5 along x
D in 2013 is more right-wing than in 2011.
When describing 'how much more right-wing is D', is it correct to describe the change in the points relatively using a %?
Change towards right = 1-(-5.6/-4.5) = '20% more right wing'
Or because the scale is finite (-10 to 10) and D has moved along one point, is D '5% more right-wing'?