Officiality of Interbull evaluations

The Interbull evaluations contain a usability code that indicates 
whether the Interbull evaluation is the official evaluation
or whether the one from only US data (USDA-DHIA) is official. The
Interbull evaluation is official if 1) it includes data from an additional
country or, 2) the US has no evaluation, or 3) Interbull excludes US data
but its reliability is higher than the US reliability. The same rules
apply to each trait group (yield, SCS, and linear type composites).