Analysis of gumtree.co.za's search volume

We can see from the graph,from January 2004 to June 2006,the search volume was 0.Since then,it started to appear,but the growth was not stable, in March 2009,the search volume was
30%,than began to decrease,then increased again.Since September 2011,it grew very rapidly.But there were several fluctuations,eventually,it reached its peak in August 2012,after that,it declined rapidly.Then had a increase again.Till June 2013,the search volume was 81%.
Across the world,gumtree.co.za is most popular in South Africa,and there is almost no search volume in other countries.