factbook.xml ids

Seem to be broken.. 21 duplicate ids (found in 7.7 secs). These are all cities in more than one province. Kansas City is in four!

import module namespace functx="http://www.functx.com";
declare variable $data:=db:open("factbook","factbook.xml");
let $i:=$data//@id
return functx:non-distinct-values($i)

f0_3099 f0_3111 f0_3123 f0_3129 f0_1533 f0_1583 f0_4275 f0_1598 f0_6017 f0_6689 f0_7122 f0_8638 f0_1715 f0_10628 f0_10634 f0_1865 f0_1875 f0_14313 f0_14419 f0_2194 f0_2237