 In the United States, use of the term "Roman Catholic", as well as the number of Catholics, began to grow only in the early 19th century.In 1790 there were only 100 Catholics in New York and some 30,000 in the whole country, with only 29 priests.As the number of Catholics in the United States grew rapidly from 150,000 to 1.7 million between 1815 and 1850—mostly by way of immigration from Ireland and the German Confederation—many clergy followed to serve this population, and "Roman Catholic parishes" were established.