Consistently Declare objects in Webservices

protected PerformanceCounter cpuUsage;// = new PerformanceCounter("Processor", "% Processor Time", "_Total");
protected PerformanceCounter ramUsage;// = new PerformanceCounter("Memory", "Available MBytes");
//protected CounterSample sample;

public monitor()
{
cpuUsage = new PerformanceCounter("Processor", "% Processor Time", "_Total");
ramUsage = new PerformanceCounter("Memory", "Available MBytes");
//sample = cpuUsage.NextSample();
}

[WebMethod]
public float getHostCpuUsage()
{
cpuUsage.NextValue();
Thread.Sleep(100);
cpuUsage.NextValue();
Thread.Sleep(100);
return cpuUsage.NextValue();
}

[WebMethod]
public float getHostMemUsage()
{
return ramUsage.NextValue();
}