opinion european central bank novemb request commiss european commun draft commiss regul ec lai detail rule implement council regul ec minimum standard treatment price reduct time enter purchas price harmonis index consum price con octob european central bank ecb receiv request european commiss ecb opinion draft commiss regul ec minimum standard treatment price reduct time enter purchas price harmonis index consum price hicp ecb compet deliv opinion base articl treati establish european commun articl council regul ec octob harmonis indic consum price accord sentenc articl rule procedur european central bank ecb opinion adopt govern council ecb draft regul minimum standard treatment price reduct object draft regul establish minimum standard treatment price reduct hicp temporari price reduct summer winter sale signific impact index result period concern differ treatment affect compar hicp draft regul defin condit price reduct reflect hicp relat purchas individu product discriminatori time purchas articl defin condit implement regul lead revis previou data chang annual rate tenth percentag point articl ecb agre propos draft regul leav open price reduct hold minimum time interv order account hicp comput ecb urg eurostat ensur fulli compar implement provis price reduct ecb welcom requir articl gener provis revis hicp adpopt futur ii draft regul time enter purchas price hicp object draft regul harmonis time enter price hicp import differ time purchas time payment deliveri consumpt good draft regul requir price record hicp month observ good purchas consum time payment deliveri consumpt ecb agre propos servic draft regul requir price enter hicp month consumpt servic commenc price price chang announc supplier agre supplier consum transact conceptu fulli consist propos treatment good lead practic transpar comprehens outcom altern option propos rule practic member state ecb accept propos ecb opinion publish offici journal european commun frankfurt main novemb presid ecb willem duisenberg