The definition of a million-selling single, as regarded by the Official Charts Company (OCC), has changed in line with new technology for music consumption. Originally only physical record sales were counted since the start of the UK Singles Chart in November 1952. Digital downloads of a track were included from 2004 onwards and from 2014 onwards BPI-certified awards (Silver, Gold and Platinum) and the weekly charts include audio streaming. In 2017, the OCC included streaming in their definition of a million-seller and published a full list of the 311 songs which had achieved this. Certified awards can also include shipments (sales to trade). The OCC and Music Week regularly announce when a record becomes a million seller.