Blast from the Past--Investigating President Carter

FiveThirtyEight has a piece on how presidents get investigated by Congress, including an interesting graph showing investigations of presidents from Nixon to Obama. 

Three points of particular interest:

• based only on eyeballing, ranking the presidents from least investigated to most (counting days of investigative hearings in the House) you get this list:
• GWBush
• Clinton!!
• Obama
• GHWBush
• then Carter, Nixon, and Reagan, much more investigated and hard to rank.
• the graph shows whether Congress was under the control of the president's party or not--which accounts for Bush's position, but what's most surprising to me is the high ranking of Carter.--if you discount Watergate, he likely was more investigated by his own party, than Nixon was by his opponents. 
• Reagan's high ranking is partly accounted for by Dem control of the House throughout his terms in office, but it's also a reminder of how rocky his administration was and the number of scandals.