In this particular case 'most' means 99.77%: > At the time of our review, approximately 44,000 of the 18.9 million numberholders were receiving SSA payments.

In this particular case 'most' means 99.77%: > At the time of our review, approximately 44,000 of the 18.9 million numberholders were receiving SSA payments. There were something like 90k centenarians in the US at the time so the amount of fraud from this category is likely some small fraction of that 0.27%.