Americans are doing better at staying on top of their mortgage loans, according to data from CoreLogic, with delinquency rates falling to their lowest point in 20 years. The national delinquency rate – mortgages with payments past due by 30 days or more – fell to 3.6% in April, the lowest rate since 1999 and lower than the 4.3% rate from a year ago. CoreLogic attributes the improvement to the past several years of more responsible underwriting and record unemployment.