title: Calculate CPU usage from ticks
body: <p>How can CPU usage be calculated in % when I know the number of CPU ticks spent in: user, nice, sys, idle, and irq? For example the output of tick values is like this:</p>
  
  <p>449760
  3590
  282250
  298612690
  0</p>
  
  <p>but I want to know their percentage value. Is there some formula for this calculation?</p>