your shipping list has a couple of extra values
for example:
<option value="PA">PA</option>
<option value="PA">PR</option>
and:
<option value="VT">VI</option>
<option value="VT">VT</option>
remove the following 2 lines from the shipping list:
<option value="PA">PR</option>
and
<option value="VT">VI</option>