| Clinton '16 | Trump '16 | Others '16 |
| 65,844,694 | 62,979,616 | 7,804,203 |
| Obama '12 | Romney '12 | Others '12 |
| 65,915,795 | 60,933,504 | 2,236,110 |
| Obama '08 | McCain '08 | Others '08 |
| 69,297,997 | 59,597,520 | 1,866,981 |
| Kerry '04 | Bush '04 | Others '04 |
| 59,028,444 | 62,040,610 | 1,225,792 |
| Gore '00 | Bush '00 | Others'00 |
| 50,999,897 | 50,456,002 | 3,949,201 |
Interesting. I kind of thought that 2000 would have about the same number of third-party votes as 2016, but it had almost exactly half as many.
More stats here...