[alain94040]

You won't find any precise numbers, because it depends on how early stage you are willing to call a startup.

Stage 0: a bunch of friends have drinks one night and dream about starting a startup. 99% will not even go further

Stage 1: one or more co-founders actually meet regularly and try to make progress on starting their startup - still about 99% will not succeed

Further stages: get an office, or quit and work full-time on the idea, or raise a small seed, etc... Still close to 99% failure rate.