The slowest sales pace for any April in 16 years indicates the spring selling season is shaping up as a bust.

Sales of previously owned homes in April declined 0.5% from March to a seasonally adjusted, annualized rate of 4 million units, according to the National Association of Realtors. That is the slowest April pace since 2009. Sales were down 2% from April of last year. Housing economists were expecting a gain of 2.7%.

U.S. existing home sales unexpectedly fell in April despite a temporary drop in mortgage rates and increased supply, and could remain lackluster this year amid rising economic uncertainty.