cluster analysis - data clustering

I have some data set which i would like to partition into 3 groups a:set 1 b: set 2 c: background. I use FindClusters[] function but as you can see (after evaluating the commands) the result is not what I am looking for.
Can someone help?

data1 = RandomReal[{-0.1, 0.1}, {10^2, 2}];
data2 = RandomReal[{-1, 1}, {2*10^2, 2}];

data3 = RandomReal[{-0.3, -0.2}, {2*10^2, 2}];
data5 = Join[data1, data2, data3];
ListPlot[FindClusters[data5, 3]]