> You could start with the number of KSI caused by cyclists compared with motor vehicles

Cyclist involved KSIs, 2013-2020: 1123 (30 + 1093)

All road KSIs, 2020: 24989 (1460 + 23529) (and this was a quieter than normal year on the roads)

I make that a factor of 8 * (24989 / 1123) or 178x difference.