Diplomatic dropped from 5% to 3%, economic history from 7% to 5%, and cultural history grew from 14% to 16%. Based on the number of full-time professors in U.S. history departments. Stephen H. Haber, David M. Kennedy, and Stephen D. Krasner, "Brothers under the Skin: Diplomatic History and International Relations", International Security, Vol. 22, No. 1 (Summer, 1997), pp. 34–43 at p. 42 online at JSTOR