vmstat displays cpu idle time at 100%

Since yesterday the vmstat command is displaying the cpu idle time at 100%At each time interval. It never changes. Not sure what it means other than it Quit calculating that stat. And I'm curious why. Using sar I can display a correctCpu idle percent, but vmstat does not. Any ideas why or suggestion to resolve.I was thinking a reboot might cure it, but it's a guess. Server has been up 83 days. We are running HP-UX B.11.11

We use vmstat constantly on all our HP-UX servers and we have never had a problem with it reporting. What make you think its wrong? Can you show some examples

We use 11.11 or 11.23.

And we hardly ever reboot.

Here is a vmstat output and following is sar output on the same server.

   procs           memory                   page                              faults       cpu
r     b     w      avm    free   re   at    pi   po    fr   de    sr     in     sy    cs  us sy id
1     0     0   438406   32431    0    0     0    0     0    0     0      0      3     1   0  0 100
1     0     0   440543   32386    2    1     0    0     0    0     0   1036  10111  4016   0  0 100
1     0     0   440543   32386    2    0     0    0     0    0     0   1035   9864  3981   0  0 100
1     0     0   440543   32386    1    0     0    0     0    0     0   1041  10358  3994   0  0 100
1     0     0   440543   32386    0    0     0    0     0    0     0   1037  10075  3973   0  0 100
1     0     0   440543   32386    0    0     0    0     0    0     0   1035   9846  3961   0  0 100
1     0     0   440543   32386    0    0     0    0     0    0     0   1039   9718  3958   0  0 100
1     0     0   440543   32386    0    0     0    0     0    0     0   1045   9575  3948   0  0 100

HP-UX egateliv B.11.11 U 9000/800 08/06/08

16:39:22 %usr %sys %wio %idle
16:39:23 1 4 0 95
16:39:24 0 4 1 95
16:39:25 0 4 1 95
16:39:26 2 3 3 92
16:39:27 1 2 1 96
16:39:28 0 3 1 96
16:39:29 0 2 1 97
16:39:30 31 9 11 48
16:39:31 32 8 26 34
16:39:32 25 8 8 59
16:39:33 36 9 17 38
16:39:34 1 4 0 95
16:39:35 0 5 2 93
16:39:36 23 5 3 69
16:39:37 44 9 7 40
16:39:38 10 8 6 76
16:39:39 0 3 0 97
16:39:40 14 6 24 56
16:39:41 31 10 30 29
16:39:42 29 6 7 58
16:39:43 0 6 1 93
16:39:44 0 3 0 97
16:39:45 0 2 0 98
16:39:46 1 5 2 92
16:39:47 1 3 1 95

Average 11 5 6 77