Delinquency rates at the country's credit card companies soared to their highest level in nearly a decade during the first quarter, amid the ongoing economic slump.

According to the financial industry on Sunday, all major local credit card firms saw an increase in delinquency rates by the end of March, which represents the percentage of payments overdue by more than one month, such as credit card bills, installment payments and credit card loans.

Hana Card reported a delinquency rate of two-point-15 percent for the January-March period, up zero-point-21 percentage points from the previous quarter and zero-point-28 percentage points from a year ago.

This marks the highest rate since Hana Card was established in December 2014.

KB Kookmin Card said its delinquency rose to one-point-61 percent, the highest level since late 2014.

Shinhan Card also recorded a delinquency rate of one-point-61 percent, the highest since the third quarter of 2015.