Official Charts Company records showed that it took four years from 2006 to reach sales of 50 million and just two further years to double that total.
Digital sales now account for over 34% of albums sold in the UK.
Adele's 21 and Ed Sheeran's + lead the bestselling digital albums of all time in the UK, with 15 of the top 25 being British artists.
"Sales of digital albums are surging ahead as British consumers embrace the convenience, value and choice offered by online services," BPI chief executive Geoff Taylor said.
"As our athletes compete against the best in the world, British artists have taken the gold and silver positions in the best-selling digital artist albums of all time, and six places in the top ten."
Overall album sales in the UK dropped by 13.8% this year, but sales of digital albums have increased by 17.3%. Digital music sales overtook physical for the first time in May.
The ten best-selling digital albums of all time in the UK, all of which have sold over 250,000 units, are:
1. Adele - 21
2. Ed Sheeran - +
3. Lady GaGa - The Fame
4. Kings of Leon - Only By The Night
5. Rihanna - Loud
6. Florence + the Machine - Lungs
7. Coldplay - Mylo Xyloto
8. Mumford & Sons - Sigh No More
9. Plan B - The Defamation of Strickland Banks
10. Bruno Mars - Doo-Wops & Hooligans
Watch Adele's video for 'Someone Like You' below: