100% of what? Those things have ECC and redundancy to the hilt. The data corruption odds are real and higher than one would expect but still not very high.
Look at pag 138...and correlation with altitude...: https://www.atsb.gov.au/sites/default/files/media/3532398/ao...
Look at pag 138...and correlation with altitude...: https://www.atsb.gov.au/sites/default/files/media/3532398/ao...