Search for Safe Financial Institutions . Updated on 01/10/2019. The Safe & Sound ratings system employs several tests to measure the capital adequacy, asset quality and profitability of each rated The Evolution of Class 5 Ratings. Initially, the decimal-system basis for the YDS capped ratings at 5.9 for the most difficult climbs at that time. As climbers’ skills and gear evolved, though, the need arose for higher ratings. Because 6.0 was already designated for aid climbing, ratings of 5.10 and above were added.