Wall Street has already been treated to a veritable tidal wave of economic data this morning, including the latest weekly crude inventories and ADP's May employment numbers. The Institute for Supply Manufacturing (ISM) added to the deluge with the release of its statistics on the nonmanufacturing sector. According to the ISM, its nonmanufacturing index dropped to 51.7% in May from April's reading of 52.0%.

The decline was smaller than most analysts expected the consensus forecast was looking for a drop to 50.0%. Readings above 50.0% indicate expansion, while readings below this benchmark reveal contraction. May's number suggests growth in the services sector, albeit sluggish growth.

On Monday, the ISM revealed that its index for the manufacturing sector edged mildly higher in May, rising from 48.6% to 49.6%. The increase was greater than analysts expected.