The rules that use the category "<degree_unit-pl>" are:

<degree_setting-not_initial_zero-90>

<degree_number-not_initial_zero-90-pl> <degree_unit-pl>

<degree_setting-180>

<degree_number-180-pl> <degree_unit-pl>

<degree_setting-360>

<degree_number-360-pl> <degree_unit-pl>