Ok but based on what?  The assumption of many is that life is exceedingly rare and that reaching the advanced stages of development yet significantly more rare.  The problem is we really have nothing to base this on other than our own singular experience. We know that life is tenacious, particularly on microscopic scales.  I would think some of the 1% odds for going from abiogensis to higher animal are an extremely pessimistic view of the odds based on the information we actualy have available.

In regards to the rarity of abiogensis interestingly enough only a few weeks ago I saw this press release:

ISRO Press Release

"In all, 12 bacterial and six fungal colonies were detected, nine of which, based on 16S RNA gene sequence, showed greater than 98% similarity with reported known species on earth. Three bacterial colonies, namely, PVAS-1, B3 W22 and B8 W22 were, however, totally new species. All the three newly identified species had significantly higher UV resistance compared to their nearest phylogenetic neighbours. Of the above, PVAS-1, identified as a member of the genus Janibacter, has been named Janibacter hoylei. sp. nov. The second new species B3 W22 was named as Bacillus isronensis sp.nov. and the third new species B8 W22 as Bacillus aryabhata.

The precautionary measures and controls operating in this experiment inspire confidence that these species were picked up in the stratosphere. While the present study does not conclusively establish the extra-terrestrial origin of microorganisms, it does provide positive encouragement to continue the work in our quest to explore the origin of life. "

Searching through a microbology journal to find information on this I came across this in FEMS Microbology Letters:

Source

"3.3 Discussion of a space origin for the isolates

An extraterrestrial origin of the isolates [17] provides a consistent, if controversial, explanation of our findings.  The bacterial material, cultured in the present experiment, and detected earlier through fluorescence microscopy, can be regarded as forming part of the 100 t day^-1 input of cometary material known to reach the Earth. Critics of panspermia may argue that 3 µm radius particles get burnt through frictional heating and end up as meteors.  Some fractions may do, but others would not. Survival depends of many factors such as angle of entry and mode of deposition in the very high stratosphere. Several modes of entry can be considered that permit intact injection into the stratosphere, possibly starting off as larger aggregates released from comets that disintegrate into a cascade of slow-moving smaller clumps at heights above 270 km where frictional heating would be negligible. Evidence for such disintegrations has been available for many years [18], and more recent studies of particles collected using U2 aircraft have also shown the survivability of extremely fragile organic structures."

My main point is that until we can show to a high degree of certainty that the formation of life is in fact rare event, a common event, or something in between, any assessment of a percentage is going to be inaccurate guessing at best.  But if this recent finding is any indication at all it looks to be much closer to the common occurence side of things than the rare occurence side.

PS - Note the press release is a result of them confirming the findings of a test done in 2001 iirc.  The FEMS pdf is from the initial experiment before they had confirmed their findings by reproducing the result.