Television ratings in Australia are used to determine the size and composition of audiences across Australian broadcast and subscription television, primarily for the purpose of informing advertisers what programming is popular with the audience they are attempting to sell their product or service to. Ratings are monitored year-round, however, viewership figures are only officially counted for 40 weeks during the year, excluding a two-week break during Easter and ten weeks over summer. Thus, the majority of locally produced programming and popular international shows on commercial networks are shown during the rating period. A 2016 report found that commercial television in Australia reaches 85.1% of the population aged over 13 years old (down from 93.1% in 2008) with viewership decreasing fastest in viewers aged under 50. The decline in free-to-air television audiences of recent years has been attributed to a tougher and more competitive environment brought about by video on demand and streaming services. History Until 1991, AGB McNair provided television ratings data, covering only homes in Sydney and Melbourne. From 1991 until 2000, 'Nielsen Media Research Australia' was the company that measured television ratings, introducing People meters for the first time. From 2001 onwards, OzTAM and Regional TAM took over. OzTAM is wholly owned by the three commercial broadcasters (Seven Network, Nine Network and Network Ten), while Regional TAM is owned by a number of regional broadcasters, however both operate independently. In total, OzTAM measures ratings from 3,500 homes, with 950 homes in Sydney, 900 in Melbourne, 650 in Brisbane and 500 each in Adelaide and Perth, with these ratings commonly referred to as 'five city metro ratings'. A further 2,000 homes outside these five cities are measured by Regional TAM, and an additional 1,200 homes monitor viewing of subscription television in Australia. Nielsen are contracted to provide the audience measurement services to both OzTAM and Regional TAM having previously operated their own measurement service. In 2017, the metropolitan homes measured will increase to 5,250. From 27 December 2009, OzTAM and Regional TAM introduced time shift ratings, measuring viewers who watch a program within seven days of its first broadcast. Ratings reports were subsequently broken out into two parts: Overnight ratings - preliminary figures combining real-time viewing and 'as live' viewing (timeshifted and watched the same day of broadcast), which are released the following calendar day at 9 am AEST. Consolidated ratings - final figures combining overnight ratings and time-shifted