Stubbornly low supply levels held down existing-home sales in April and also pushed the median number of days a home was on the market to a new low of 29 days, according to the National Association of Realtors.

Total existing-home sales which are completed transactions that include single-family homes, townhomes, condominiums and co-ops, dipped 2.3 percent to a seasonally adjusted annual rate of 5.57 million in April from a downwardly revised 5.70 million in March. Despite last month's decline, sales are still 1.6 percent above a year ago and at the fourth highest pace over the past year.