In the context of credit risk assessment, the Merton model is often used to estimate the default risk of firms by calculating the 'distance to default.' Consider the following data derived from the Merton model for three counterparties, Company P, Company Q, and Company R. These companies operate within the same industry and do not pay dividends. Based on the calculated distance to default over a 1-year period, how should a credit manager rank these companies in terms of their likelihood of defaulting?