How to calculate explained variability in cluster analysis in STATA for elbow plot?

[Gianfranco Di Gennaro]

Dear all,
I'm doing a cluster analysis of binary variables in STATA.

cluster averagelinkage var1 var2 var3 var4 var5 var6 var7 var8 var9 var10 var11, measure(Gower2)

Next I have to search for the most suitable number of cluters.
For example here I try to use 5 clusters:

cluster gen ak=gr(5)

I would like to use the elbow method to optimize the number of clusters.

The question is: Is there a way to compute the explained variability and then graph it for the different numbers of clusters?

Thank you all in advance.
Gianfranco