viewing watched within 7 days of initial broadcast, which are released the afternoon of the following week. In October 2014, Australia became the third country to introduce Nielsen Twitter TV ratings, measuring reach and activity of television related discussions on the social media platform. From 3 April 2016, OzTAM began releasing timeshift viewing data for programs watched up to 28 days after broadcast, noting that genres such as dramas, mini-series and films could add up to 20% of their audience with the new data, even though viewing between 8 and 28 days after initial broadcast accounted for only 1.8% of total television viewing. Measurements In Australian media, the most common ratings metric reported publicly is total viewers of a program from all age groups. However, advertisers typically prefer the viewership of demographic ranges based on the type of viewers they are seeking to promote their product to. The three common aged-based demographic groups, known as the 'key demographics,' include people aged 16 to 39, 18 to 49 and 25 to 54. In advertising and media, the reporting of ratings has historically been confined to what is known as '5 city metro,' which only includes viewership of the OzTAM panels in the five largest cities (Sydney, Melbourne, Brisbane, Adelaide, and Perth). Since the 2010s, it has become more common for television networks to publicly spruik 'national ratings' which combine the 5 city metro audience with ratings from Regional TAM. Ratings performance In 1989, for the first time since 1978, the Seven Network overtook its rivals Nine Network and Network 10 in terms of average viewers and have remained ahead of Nine and Ten every year until 1994, where due to lower ratings than expected, and a launch of new programs not performing as hoped, the Nine Network defeated Seven Network and regained the title as the highest rating television network in Australia, with the latter relegated back to second highest for the first time in twelve years. In 1990, for the first time since OzTAM began, the Seven Network won all forty weeks of the official ratings period, and, as of 1994, has won the last five years of ratings consecutively throughout the late 1980s and early 1990:. From 1994 up until 2004, the Nine Network had generally been the ratings leader in Australia, typically followed by the Seven Network and Network Ten respectively. While Network Ten generally rates lower in