sar -u command is reporting 0% idle in Red Hat Enterprise Linux 4

Issue

sar -u command is reporting 0% idle in Red Hat Enterprise Linux 4 while top and iostat are showing 98% idle

sar -u 
Linux 2.6.9-42.ELsmp (XXXXXX)         05/24/10 

04:41:26          CPU     %user     %nice   %system   %iowait     %idle 
04:41:28          all      0.00      0.00      0.00      0.00      0.00 
04:41:30          all    100.00      0.00      0.00      0.00      0.00 
04:41:32          all      8.74      0.00     78.64     12.62      0.00 
04:41:34          all      1.97      0.00     98.03      0.00      0.00 
04:41:36          all      1.97      0.00     95.57      2.46      0.00 
Average:          all      3.53      0.00     92.94      3.53      0.00