Browsing through U.S Law, I noticed that there are many notes- e.g. memos to Federal employees and executive orders. In some cases these have a signature block, which shows who wrote the document. Most, but not all, are written by presidents. I suspect that either the inclusion of these records in U.S. Law (or at least the signatures) is relatively modern, as the oldest person with multiple signatures is Harry Truman- these are somewhat, but not entirely chronological.

Barack Obama: 183 William J. Clinton: 159 George W. Bush: 147 Jimmy Carter: 65 Ronald Reagan: 59 George Bush: 55 Richard Nixon: 37 Dwight D. Eisenhower: 32 Lyndon B. Johnson: 28 Gerald R. Ford: 17 Harry S Truman: 13 John F. Kennedy: 10 Harry S. Truman: 7 Franklin D. Roosevelt: 4 Fred M. Vinson: 1 Halifax.: 1 Nancy Pelosi: 1 Wm. H. Taft.: 1 Robert F. Kennedy: 1 By Alexander C. Hoffman: 1 Franklin D Roosevelt: 1 Robert C. Byrd: 1 By Sheldon Elliott Steinbach: 1 Edward DLG. Pangelinan': 1 By Irwin Karp: 1 Ambassador F. Haydn Williams: 1 Robert S. McNamara: 1 J. C. Lambert: 1

This output can be easily generated in Python, like so:

all_signatures = [] def findElements(xpath, urls): for root, dirs, files in os.walk(dir): for f in files: if f.endswith('.xml'): tree = ET.parse(dir + "\\" + f) namepath = './/{http://xml.house.gov/schemas/uslm/1.0}name' sigpath = './/{http://xml.house.gov/schemas/uslm/1.0}signature' signatures = [n.find(namepath).text \ for n in tree.findall(sigpath)] print(f) print(Counter(signatures)) all_signatures = all_signatures + signatures print("All:") print(Counter(all_signatures))

The distribution of these is interesting as well, as certain titles are represented much more than others (it would be best to normalize these by the length or age of the title, although that may be less useful given the recency bias of the signatures).

The two largest (Title 22, Title 42) are “Foreign Relations and Intercourse” and “The Public Health and Welfare”.

Title 01: 3 memos Title 02: 10 memos Title 03: 24 memos Title 04: 2 memos Title 05: 87 memos Title 06: 14 memos Title 07: 17 memos Title 08: 19 memos Title 09: 0 memos Title 10: 36 memos Title 11: 0 memos Title 12: 9 memos Title 13: 0 memos Title 14: 0 memos Title 15: 48 memos Title 16: 27 memos Title 17: 5 memos Title 18: 10 memos Title 19: 40 memos Title 20: 16 memos Title 21: 5 memos Title 22: 114 memos Title 23: 3 memos Title 24: 1 memos Title 25: 5 memos Title 26: 8 memos Title 27: 0 memos Title 28: 14 memos Title 29: 11 memos Title 30: 1 memos Title 31: 28 memos Title 32: 2 memos Title 33: 10 memos Title 35: 1 memos Title 36: 8 memos Title 37: 2 memos Title 38: 8 memos Title 39: 2 memos Title 40: 12 memos Title 41: 14 memos Title 42: 122 memos Title 43: 6 memos Title 44: 6 memos Title 45: 1 memos Title 46: 1 memos Title 47: 5 memos Title 48: 20 memos Title 49: 19 memos Title 50: 33 memos Title 51: 6 memos