In the United States, the merger is widespread everywhere but is quite recent in some parts of the country. For example, fieldwork performed in the 1930s by Kurath and McDavid shows the contrast to be robustly present in the speech of Vermont, northern and western New York State, Virginia, central and southern West Virginia, and North Carolina as well as the whole Atlantic coast (North and South). However, by the 1990s, telephone surveys conducted by Labov, Ash, and Boberg (2006) show those areas as having completely or almost completely undergone the merger. Even in areas in which the distinction is still made, the acoustic difference between the of "horse" and the of "hoarse" were found to be rather small for many speakers. In the 2006 study, most white participants in only these American cities still resisted the merger: Wilmington, North Carolina; Mobile, Alabama; and Portland, Maine. A 2013 study of Portland, however, found the merger to have been established "at all age levels." In the 2006 study, even St. Louis, Missouri, which traditionally maintained the "horse"–"hoarse" distinction so strongly that it instead merged "card" and "cord", showed that only 50% of the participants still maintained the distinction. The same pattern (a "horse"–"hoarse" distinction and a "card"–"cord" merger) also exists in a minority of speakers in Texas and Utah. New Orleans prominently shows much variability regarding the merger, including some speakers with no merger at all. Black Americans are rapidly undergoing the merger but are also less likely to do so than white Americans, with a little over half of the 2006 study's black participants maintaining the merger nationwide.