: American Academy of Arts and Sciences, Humanities Indicators (humanitiesindicators.org). Plotted values obtained from annual reports in the “Doctorate Recipients from U.S. Universities” series published by the National Science Foundation. All reports and online data resources are available at https://www.nsf.gov/statistics/doctorates/
. Table numbers for years: 1994 to 1998—A-3; 1999 to 2001, 2005—18; 2002 to 2004—17; 2006, 2008—20; 2007—S-20; 2009—24; and 2010 to 2014—27.