The article
https://en.numista.com/catalogue/pieces54956.html
gives the distribution by years for 2014 in 4 lines:
2014 5 000 000 55%
2014 25 000 13% In sets BU
2014 19 014 0.6% In sets UNC
2014 5 000 0.7% Proof
.
Note. Obviously the percentage is from wrongly described occurrence of lines and has nothing to do with frequency as it expected to be. This is not the case of this topic.
There is no indication, how to distinguish between sets "In sets BU" and "In sets UNC". More over these two lines are inconsistent with 1,2 5, 20, 50 euro cents, 1, 2 euro coins 2014 articles, where there is just one (not two!) line with 'in sets' remark.
In which way is it possible to make the attribution
'in sets'
"In sets BU"
"In sets UNC"
correctly?