Vowels 2 and 20, /ɪ/ and /ʊə/   9 pairs     [lidlured.html]

Vowel /ɪ/ is here spelled <i>. The /ʊə/ diphthong is <oor>, <our> or <ure>. This dictionary has /bʊən/ as the only pronunciation of bourn (meaning stream or boundary). Other dictionaries give that as an alternative to /bɔn/, which would make the word a homophone of born, reducing the number of minimal pairs to 5.

The contrast is not a problem for any known group of learners.

The mean density is insignifcant at 0%. There are 8 semantic distinctions, making for a loading of 86%, or 100% if bourn is excluded.
bin bourn
  bins bourns
biz boors	
krill crewel
krill cruel
lid lured
Liz lures
mid moored
Ms Moors 
Geographical: Outside English-speaking countries, most visitors are from Yemen, Hong Kong, India, Nigeria, Spain and Malaysia. Average 5 visitors per month.

John Higgins, Shaftesbury, July 2014