En synthèse : Here are the highlights for the Second Life Economy as a whole in 2009:

Financial

•      User-to-User transactions in 2009 totaled US$567 million in 2009, growth of 65% over 2008.
•      The total amount of virtual currency in circulation reached L$6.95 billion, growth of 23% over December 2008
•      The US Dollar value of L$ in circulation totaled US$26.5 million in December 2009
•      Sales of User Generated virtual items on Xstreet SL, reached L$1.6 billion or US$6.1 million, growth of 74% over 2008   

•      The total US dollar value of all Linden dollars traded on the LindeX™ currency exchange in 2009 reachedgrowth over 2008 US$115 million in value,  7%

•       The total US dollar value of all Linden dollars traded on the Xstreet SL™ currency exchange in 2009 reachedgrowth over 2008 US$1.5 million in value, 169%

Usage

•      Residents spent 481 million hours in Second Life in 2009, 21% growth over 2008 
•      User hours lost to downtime as a portion of total user hours were down 66%, to a best-ever low of 0.19% for the whole year 
•      Monthly Repeat Logins reached an all-time high of 769,000 in December 2009, 15% growth over December 2008

Land

•     Resident-owned regions reached 23,900 in December 2009, up 6% over December 2008
•    Total Resident-owned land (including Mainland) reached 1.85 billion square meters in December 2009, up 7% over December 2008 

Source : https://blogs.secondlife.com/community/features/blog/2010/01/19/2009-end-of-year-second-life-economy-wrap-up-including-q4-economy-in-detail