Just one in 20 of the UK's best-selling tracks in 2012 were both soley written and performed by the same act, Music Week research shows.
In the Official Top 100 Singles of 2012, 90% involved at least some additional songwriting to the recording act, whilst 5% were cover versions.
That left just five of the top 100 sellers penned by the artist/s alone - including The Lumineers (pictured, Ho Hey), Swedish House Mafia (Greyhound), Sam and the Womp (Bom Bom) and Calvin Harris & Example (We'll be Coming Back).
Some cases see artists write up to 95% of the track - for example, if producer Brian Eno contributes to a Coldplay song.
However, the Top 10-selling tracks of the year, which you can see below, were all either cover versions or songs that had multiple song-writing credits.
The highest-selling track written solely by the artist was Rudimental & John Newman (Feel The Love), which was the 15th biggest single of 2012, according to Official Charts Company data.
- Gotye, Somebody That I Used To Know (Island)
- Carly Rae Jepsen, Call Me Maybe (Interscope/Polydor)
- Fun feat Janelle Monae, We Are Young (Atlantic/Fulled By Ramen)
- David Guetta, Titanium (Parlophone)
- James Arthur, Impossible (Syco/Sony)
- Psy, Gangnam Style (Island)
- Nicki Minaj, Starships (Cash Money/Island)
- Jessie J, Domino (Lava/Island)
- Maroon 5, Payphone (A&M/Octone/Polydor)
- Flo Rida, Wild Ones (Atlantic)
Source: Official Charts Company