Yes; that was it, President Garfield was shot at the B&P Station in Maryland! I recall one physician rather insinuated himself as chief medical officer for Garfield...and this fellow did not believe in the rather new concept of sterile technique. So the biography records that Garfield would very likely have survived the gunshot, had not physicians continually probed the would with 'dirty' hands, instruments.
I browsed through the lists you found...what surprised me is the two countries with only one recorded political assassination each. Hungary for one, although perhaps that might be related to the partitioning, that is Hungary was part of Austria, and so such killings did not get recorded as Hungarian?
But...Norway? Only one assassination recorded in history; even neighbor Sweden has lots!
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And, what I am now pondering with the USA is that in the 19th century, even with two presidential assassinations, still presidential protection was not taken all that seriously. Then in the 20th century, the danger seems to have begun with Hoover, taking office in 1929...coinciding with the onset of the Great Depression...and from then on, every president has apparently been threatened excepting only Eisenhower and LBJ...