DisplaySearch estimates that AMOLED revenue in 2011 reached $3.36 billion on 90 million units. Revenue grew by 169% (from $1.25 in 2010) and unit shipments grew 97%. Revenue grew faster then units because the average smartphone display is getting larger. According to DisplaySearch, AMOLED share of the small/medium display market is now 12% (up 6% in 2010).
These numbers are actually lower than what DisplaySearch estimated back in August 2011. Back then they said unit shipments will be 128 million and revenue will reach $4 billion.