Header cpu %'s don't match reality or per-process usage

The header of top (i.e the part that looks as below) is frequently reporting unlikely result. With high load it is reporting mostly idle, even though the per-process cpu usage is reporting multiple processes with 100% and one with 200% cpu usage on a multicore machine.

The numbers don't make sense and don't match the kind of numbers reported in trusty.

There is clearly some funkiness in what the header is reporting.

top - 22:14:53 up 8:31, 2 users, load average: 4.39, 4.79, 5.07
Tasks: 323 total, 2 running, 321 sleeping, 0 stopped, 0 zombie
%Cpu(s): 33.9 us, 4.4 sy, 0.0 ni, 61.5 id, 0.0 wa, 0.0 hi, 0.1 si, 0.0 st
KiB Mem : 65937708 total, 5825444 free, 24041364 used, 36070900 buff/cache
KiB Swap: 67067900 total, 67037844 free, 30056 used. 41123072 avail Mem