You would have to factor in where cycling might have been without the introduction of the new legislation - (you would need to have some good long term figures to extrapolate a decent projection).
If we put in a hypothetical general upwards direction in cycling uptake (red line) - without the introduction of the new law - we might see the that the figures in a new light.
There very may well be a permanent offset of cycling uptake (from [B] onwards) - long term damage to the numbers taking up cycling - even though it is bigger now than it was before - the figures still may be XX% lower (the offset) than they would be without the mandatory cycle helmet use law.
but . . .
You would have to factor in where cycling might have been without the introduction of the new legislation - (you would need to have some good long term figures to extrapolate a decent projection).
If we put in a hypothetical general upwards direction in cycling uptake (red line) - without the introduction of the new law - we might see the that the figures in a new light.
There very may well be a permanent offset of cycling uptake (from [B] onwards) - long term damage to the numbers taking up cycling - even though it is bigger now than it was before - the figures still may be XX% lower (the offset) than they would be without the mandatory cycle helmet use law.