This was 30 percent for the full year in 2011, it said.
"Approximately 40 percent of all phones sold in third quarter were smartphones and the growth of smartphone data traffic is expected to exceed the overall average," Ericsson Mobility report said.
It added that as only around 15 percent of the worldwide installed base of mobile phone subscriptions uses smartphones, there is considerable room for further uptake.
"Expectations of mobile-network quality have been elevated by the availability of smartphones and tablets that have changed the way we use the Internet. Mobility is becoming an increasingly significant part of our daily lives," Ericsson Senior Vice President and Head of Strategy Douglas Gilstrap said in a statement.
Total smartphone subscriptions will reach 1.1 billion by the end of 2012 and are expected to grow to 3.3 billion in 2018, it said.
Data traffic doubled between third quarter of 2011 and third quarter of 2012, and is expected to grow at a compound annual growth rate (CAGR) of around 50 percent between 2012 and 2018, driven mainly by video, it said.
The report further added that Asia Pacific (which includes India) had the largest share of the total mobile data traffic in 2012. The region is expected to increase its share of data volume from around one third today to almost 40 percent in 2018.
"3G and mobility are addictive. In India the entire premise of mobile broadband is very strong. The traffic in networks is growing and this will be driven by new subscribers," Ericsson India Head of Region Fredrik Jejdling said.
The report added that globally mobile penetration reached 91 per cent in Q3 of 2012 and mobile subscriptions total around 6.4 billion. However, the actual number of subscribers is around 4.3 billion, since many have several subscriptions.
"China alone accounted for around 35 percent of net additions, adding around 38 million subscriptions," the report said.
However, the number of mobile subscriptions in India declined by around 18 million in the quarter.
"The reason is an increased focus on active subscriptions, with the decline coming from the removal of inactive subscriptions," it said.