The reason why you are getting a 0 and that is it, is because the only item you are adding to ur list box after the first line is the value of salary.
ListBox1.Items.Add(salary.ToString)
if you are looking to print out the value in wach of the survey items from 0-8 then you would need to do something like this, after you case statement. All the case statement is doing is checking the value of salary and then increment the correct item with the array survey. Not adding them to the list box.
Something like this would add all of the items from survey into the listbox.
For i = 0 To 8
ListBox1.Items.Add(survey(i).ToString)
Next i
Cheers,
Chris