Here's some stats:-
https://www.gov.uk/government/statistical-data-sets/tsgb01-modal-comparisons
This one specifically (Passenger casualty rates by mode 2004-2013):-
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/244148/ras53001.xls
But these are probably the stats that they've looked at to single out cycling and motorcycling specifically.
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Here's some stats:-
https://www.gov.uk/government/statistical-data-sets/tsgb01-modal-comparisons
This one specifically (Passenger casualty rates by mode 2004-2013):-
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/244148/ras53001.xls
But these are probably the stats that they've looked at to single out cycling and motorcycling specifically.