Most of the Champagne produced today is "Non-vintage", meaning that it is a blended product of grapes from multiple vintages. Most of the base will be from a single year vintage with producers blending anywhere from 10 to 15% (even as high as 40%) of wine from older vintages. If the conditions of a particular vintage are favourable, some producers will make a vintage wine that must be composed of 100% of the grapes from that vintage year. Under Champagne wine regulations, houses that make both vintage and non-vintage wines are allowed to use no more than 80% of the total vintage's harvest for the production of vintage Champagne. This allows at least 20% of the harvest from each vintage to be reserved for use in non-vintage Champagne. This ensures a consistent style that consumers can expect from non-vintage Champagne that does not alter too radically depending on the quality of the vintage. In less than ideal vintages, some producers will produce a wine from only that single vintage and still label it as non-vintage rather than as "vintage" since the wine will be of lesser quality and the producers have little desire to reserve the wine for future blending.