Pending sales of existing U.S. homes fell in April to their lowest marks in four years, according a National Association of Realtors index released today.

The index based on signed purchase agreements in April fell to 101.4, a drop of 3.2 percent for the month. The index was down 4.5 percent in March and currently stands 10.2 percent lower than April last year.

The index is considered a leading indicator since it tracks contract signings. The association also tracks closings. The group reported last week that existing home sales dropped 2.6 percent in April, the lowest level in four years.