Final answer:
Over 45% of American families carry credit card debt, suggesting that at least 45% of Americans use credit cards for their purchases.
Step-by-step explanation:
The percentage of Americans who use credit or debit cards for some of their purchases can vary depending on the source and time period. However, based on the given information, we can estimate that over 45% of American families carry some credit card debt. This suggests that at least 45% of Americans use credit cards for their purchases. It's important to note that this percentage may be higher as it is based on families with credit card debt and does not account for individuals who use credit or debit cards without carrying a balance.