The relative order in which the classifier sets associated with this block are applied, with regard to other classifiers sets within the block. Higher numbers represent block members with higher precedence. Block members with higher precedence are applied before members with lower precedence. Precedence values must be unique across members of the same classifier block when block members are evaluated in a specific order. Precedence values must be the same across block members when they are evaluated simultaneously. Version 1/2 attribute.