There are under 1,201 principal investigators in the National Institute of Health .
With 1,201 principal investigators and more than 4,000 postdoctoral fellows in basic , translational , and clinical research , the IRP is the largest biomedical research institution in the world , while , as of 2003 , the extramural arm provided 28 % of biomedical research funding spent annually in the U.S. , or about US $ 26.4 billion .
National Institutes of Health