Hi-- the question is a little vague; seems to be a math question more than nursing. If you are seeking to compare the frequency with which each ICU used an intervention, percentage of total is one way to do that, and fits with this questions's given information. So:
1. 437:100% as 59:x %
Cross multiply this equation as follows: 5900/437 = 13%.
2. 222:100% as 77:x %
Cross multiply as follows: 7700/222 = 34%
3. 762:100% as 91:x %
Again, cross multiply as follows: 9100/762 = 11.9 or 12%.
Therefore, the answer is yes; there is a difference in the rate of intervention among these ICUs. 1) used the intervention 13% of the time; 2), 34% of the time, and 3), 12% of the time. Hope this helps!