code: public float getCpuUsagePercent() {
  		if (nanoBefore == null || cpuBefore == null) {
  			throw new IllegalStateException("nanoBefore or cpuBefore where null: nanoBefore: " + nanoBefore + ", " +
  					" cpuBefore: " + cpuBefore);
  		}
  		long cpuAfter = processCpuTime.getProcessCpuTime();
  		long nanoAfter = System.nanoTime();
  
  		float utilisation = ((float)(cpuAfter - cpuBefore)) / (nanoAfter - nanoBefore);
  		return utilisation / Runtime.getRuntime().availableProcessors();
  	}
docs: Gets the average CPU utilisation since the last call of {@link CpuUtilisationWatch#start()}
  
  @return the average CPU utilisation since the last call of {@link CpuUtilisationWatch#start()}