The Purchasing Managers Index for non-manufacturing businesses has shown growth for 38 consecutive months. But the PMI slid from 54.4 to 53.1, indicating growth slowed.
In the index, above 50 indicates growth and below 50 indicates contraction.
The index for new orders also showed growth nominally slower than in March, with fresh business orders dropping from 54.6 to 54.5, but keeping the category above 50 for the 45th consecutive month.
The Employment Index, which tracks the number of employees, remained above 50 for the ninth consecutive month but slid from 53.3 to 52.
The index for new export orders dropped from 56.5 to 53.5.
Inventories, in a growth pattern for 191 consecutive months, picked up the pace, with the index up 1 point from 59.5 to 60.5.
Fourteen of 18 non-manufacturing industries showed growth while four showed declines.
Transportation and warehousing notched the largest gain, followed by retail trade, accommodation and food service, construction and company management.
Declines were led by mining, with lesser decreases in educational services, healthcare and social assistance.