The continuous element of the GHS includes questions about alcohol consumption on the heaviest day during the week prior to interview. These questions were introduced in 1998 following the publication, in 1995, of an inter-departmental review of drinking (see Chapter 9). Also included in 1998 was the measure which had been in use since 1984 based on average weekly consumption over the past year. During the review of the GHS it was agreed that data required to continue this trend series would be collected every two years in the form of a trailer.