-4.6% Gen X are the most indebted Americans followed by the Baby Boomers. The breakdown of debt by age group suggests the typical American’s debts grow with adulthood to a certain age, at which point it begins to taper off. Download the Generational Power Report (.pdf) Digging Deeper The types of debt vary in significance for each generation. For instance, the leading source of debt for Gen Z and Millennials are student loans (20%) and credit card bills (25%), respectively. Mortgages on the other hand, are the leading source of debt for Gen X (30%) and Baby Boomers (28%).