The research interests of historians change over time, and there has been a shift away from traditional diplomatic, economic, and political history toward newer approaches, especially social and cultural studies. From 1975 to 1995 the proportion of professors of history in American universities identifying with social history increased from 31 to 41 percent, while the proportion of political historians decreased from 40 to 30 percent. In 2007, of 5,723 faculty in the departments of history at British universities, 1,644 (29 percent) identified themselves with social history and 1,425 (25 percent) identified themselves with political history. Since the 1980s there has been a special interest in the memories and commemoration of past events—the histories as remembered and presented for popular celebration.