In the first decade following the founding of the British Labour party, the number of people regularly voting for Labour increased fivefold  The number of committed Labour voters increased a further fivefold during the party' s second decade
Since the increase was thus the same in the first as in the second decade, the often-made claim that the Labour party gained more voters in the party' s second decade than in its first is clearly false
relies on statistical evidence that, strictly speaking, is irrelevant to establishing the conclusion drawn