Determine different clusters of 1d data from database
I am trying to detect clusters, i.e. segments on a linear scale, with visibly higher concentration of distribution elements. Consider the following simplified distribution
VAR01=3 VAR02=17 VAR03=18 VAR04=21 VAR05=23 VAR06=44 VAR07=61 VAR08=89 VAR09=90 VAR10=92 VAR11=94 VAR12=117
If you put these values on a diagram, you could see that there is a visible concentration (cluster) between 17-23 and 89-94 with VAR01, VAR06, VAR07 and VAR12 being lone outliers.
What are the best techniques in programmatically recognizing such clusters in a distrubution?