An INGO may be founded by private philanthropy, such as the Carnegie, Rockefeller, Gates and Ford Foundations, or as an adjunct to existing international organizations, such as the Catholic or Lutheran churches. A surge in INGOs for economic development occurred during World War II, some of which would later become large organizations like SOS Children's Villages, Oxfam, Catholic Relief Services, CARE International and Lutheran World Relief. The number of INGOs grew from 6,000 in 1990 to 26,000 in 1999, and a 2013 report estimated about 40,000.[5]