How so? The way I calculate it, the percentage of GOP voters to the total has increased from ~ 42.97% to 44.2% Where do you get 5%?
55469/129089 vs. 60851/137657
raw numbers not percentages
Democrats decreased from 57.03% to 55.8%.
That's a net benefit to Republicans of (57.03-55.8) + (44.2-42.97) = 2.46% of the total vote. As a percentage of the initial Republican population, this would be equivalent of increasing the population of Republicans by 5%.
Another way of looking at it is to consider the impact if turnout of Republicans increased by 5%; that is, 5% more Republicans than prior turnout.
With the close elections we have been seeing, such an increase in turnout would be a game-changer. Again, the benefit will only be that great if the independent vote shows a similar shift.