Help with my Process Viewer

Question

hi, im trying to show the % of the cpu that is being used With A persific process. i have found out how to do it but it dubbles what it really is. also if i do Total it shows "200" i see that it is going form the Task-manager and totaling it all up any help please? hear is my code for example if i tell it to show how much CPU usage is being used by "firefox" in task-manager is shows 4 and in my program it shows 8

 Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        PerformanceCounter1.CategoryName = "Process"
        PerformanceCounter1.CounterName = "% Processor Time"
        PerformanceCounter1.InstanceName = (ListBox1.SelectedItem)


    End Sub



    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim pList() As System.Diagnostics.Process = _
System.Diagnostics.Process.GetProcesses
        For Each proc As System.Diagnostics.Process In pList
            ListBox1.Items.Add(proc.ProcessName)
        Next
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        'ListBox1.
    End Sub


    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        NumericUpDown1.Value = (CInt(PerformanceCounter1.NextValue))

        TextBox1.Text = NumericUpDown1.Value
        Label1.Text = PerformanceCounter1.InstanceName
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub
End Class