From Eric Nichols on the Randon group:
A kind anonymous soul has put together this searchable website of all PBP results from 1931 through 2019:
It’s searchable by year, country, bike type, start group, etc.
The 2019 numbers are probably unofficial results scavenged from various data sources.
The finishing rate in 2019 was the lowest in history at 69.2%.
The legendarily wet year 2007 was slightly higher at 69.9%
The 2019 results include finishers with incomplete control data, some of which may not be homologated, so the actual finishing rate may be lower.
Among the countries with >100 participants, the UK and Switzerland had the highest finish rates at 87 and 88%
US finish rate was 77%, slightly lower than most European countries which tended to be >80%.
The finishing rate was especially low for hot countries such as India (15%), Taiwan (34%), and Thailand (19%).
Headwinds and low nighttime temperatures are likely contributing factors.