The GPG in unadjusted form represents the difference between average gross hourly earnings of male paid employees and of female paid employees as a percentage of average gross hourly earnings of male paid employees.

• Council Regulation (EC) No 530/1999 of 9 March 1999 concerning structural statistics on earnings and on labour costs
  Place of publication: (Dz. Urz. WE L 63 z 12.03.1999, str. 6-10, z późn. zm. – Dz. Urz. UE Polskie wydanie specjalne, rozdz. 5, t. 3, str. 341, z późn. zm.)