(12)The same calendar should be applied irrespective of the reason for which the exposure is non-performing. The prudential backstop should be applied at an exposure-by-exposure level. A calendar of three years should apply for unsecured NPEs. In order to allow institutions and Member States to improve the efficiency of restructuring or of enforcement proceedings, as well as to recognise that NPEs secured by immovable collateral and residential loans guaranteed by an eligible protection provider as defined in Regulation (EU) No 575/2013 will have a remaining value for a longer period of time after the loan has been classified as non-performing, it is appropriate to provide for a calendar of nine years. For other secured NPEs a calendar of seven years should apply in order to build up full coverage.