inertia per iteration: 320.5 224.5 213.7 212.4 211.9 211.7 211.7
         customers  recency  frequency  monetary
segment                                         
0               39      5.0        4.0     197.0
1               58    106.0        3.0     153.0
2               89     51.0       10.0     469.0
3               67      6.0       20.0    1057.0
