originally i worked it out at +40% but i re-did it earlier with a different calculation and to double check used the conversion chart on the whiteline website and got 60%
with the standard bar being hollow its harder to work out
the OEM 21.7mm hollow bar is equivalent to a 20.45mm solid bar
so using the calculations and the whiteline chart a 23mm bar is around +60% and 24mm around +90%