Concurrent calls not working for per session mode in WCF

Question

I have a service code :

[ServiceContract]
public interface IService1
{
    [OperationContract]
    void MyOperation1();
}
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession,ConcurrencyMode=ConcurrencyMode.Multiple)]
public class service1 : IService1
{
    public service1()
    {
        Console.WriteLine("creating instance");
    }
    public void MyOperation1()
    {
        Console.WriteLine("starting..");
        Console.WriteLine(System.Threading.Thread.CurrentThread.ManagedThreadId);
        Thread.Sleep(1000);
        Console.WriteLine("Ending..");
    }
}

I have a client code:

static void Main(string[] args)
    {
        Thread[] t = new Thread[10];
        NetTcpBinding myBinding = new NetTcpBinding();
        EndpointAddress myEndpoint = new EndpointAddress("net.tcp://localhost:8000/MyService");
        ChannelFactory<IService1> myChannelFactory = new ChannelFactory<IService1>(myBinding, myEndpoint);
        IService1 instance = myChannelFactory.CreateChannel();
        for (int i = 0; i < 10; i++)
        {
            t[i] = new Thread(new ThreadStart(delegate() 
            {
                instance.MyOperation1();
            }));
        }
        for (int i = 0; i < 10; i++)
        {
            t[i].Start();
        }          
    }

My calls to service are being proccessed one by one. Can I get the calls concurrently processed?