Hello Stata Experts,

I am trying to create lorenz curves for a variable with four categories. I have done this before but this time my curves are coming out as straight lines. I am sharing an example dataset along with my commands.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float raw_rank1 byte v190 float(sei z) double rank float rank2
1519 2  -.57867503 0 .438 .438
1521 2  -.57797277 0 .439 .439
 890 1   -.8061847 0 .273 .273
2461 2 .0007149702 0 .655 .655
2061 2  -.28932393 0  .56  .56
2988 3    .4960965 0 .763 .763
1394 2   -.6336712 0 .407 .407
 119 1  -1.0780907 0 .045 .045
1511 2   -.5812709 0 .435 .435
 158 1  -1.0511917 0 .057 .057
3132 3    .6742755 0 .805 .805
1028 1   -.7624822 0 .311 .311
1493 2   -.5876991 0 .431 .431
1592 2   -.5417551 0 .451 .451
3225 3    .8141427 0 .822 .822
1406 2   -.6303535 0 .409 .409
1921 2   -.3819044 0 .526 .526
 266 1  -1.0056158 0 .092 .092
2282 2  -.14398591 0 .611 .611
  11 1   -1.223736 0 .001 .001
  66 1  -1.1141272 0 .027 .027
3905 3    2.594721 0 .983 .983
1562 2   -.5555258 0 .446 .446
 212 1  -1.0261097 0 .075 .075
 277 1  -1.0024703 0 .098 .098
3750 3   1.9207685 0 .949 .949
 114 1   -1.080746 0 .044 .044
 414 1   -.9529806 0 .141 .141
1021 1   -.7646693 0 .308 .308
3956 3    2.976368 0 .992 .992
2139 2   -.2403019 0 .576 .576
 872 1   -.8127694 0 .267 .267
1201 1   -.7066278 0 .357 .357
  42 1  -1.1533086 0 .019 .019
1211 1   -.7038143 0 .359 .359
 673 1   -.8647565 0 .215 .215
  61 1   -1.119929 0 .024 .024
2684 3    .1753951 0   .7   .7
2035 2   -.3084227 0 .552 .552
1706 2   -.4945633 0 .477 .477
 106 1  -1.0862021 0 .041 .041
 445 1   -.9433951 0  .15  .15
3025 3   .53929883 0 .775 .775
3368 3   1.0676816 0 .868 .868
2483 2  .011977144 0 .658 .658
1341 2   -.6609402 0 .392 .392
 123 1    -1.07341 0 .047 .047
3627 3   1.5838754 0 .929 .929
 942 1   -.7906448 0 .286 .286
2722 3   .20741607 0  .71  .71
3233 3    .8326448 0 .823 .823
1628 2  -.52488875 0 .461 .461
2923 3    .4188752 0 .753 .753
3454 3   1.2099286 0  .89  .89
1757 2   -.4668162 0 .489 .489
1435 2   -.6137782 0 .416 .416
2478 2  .008811969 0 .657 .657
3957 3     2.99273 0 .993 .993
1430 2   -.6182839 0 .414 .414
 964 1   -.7837582 0 .292 .292
1427 2   -.6187509 0 .412 .412
 927 1    -.795358 0 .282 .282
1634 2   -.5228623 0 .463 .463
 645 1   -.8762712 0 .206 .206
3474 3    1.252518 0 .894 .894
2442 2 -.012976546 0  .65  .65
 735 1   -.8494613 0 .237 .237
1143 1   -.7286108 0 .345 .345
2302 2   -.1215786 0 .617 .617
1652 2   -.5176178 0 .467 .467
 561 1   -.9010396 0 .187 .187
3317 3    .9688857 0 .854 .854
  73 1  -1.1084094 0  .03  .03
3866 3   2.3716063 0 .973 .973
 319 1   -.9914252 0  .11  .11
2440 2 -.013812775 0 .649 .649
  26 1  -1.1747433 0 .012 .012
 258 1  -1.0091702 0 .089 .089
1556 2   -.5576935 0 .445 .445
 322 1    -.990563 0 .112 .112
2132 2  -.24586444 0 .574 .574
 801 1   -.8318206 0 .254 .254
 711 1    -.856173 0 .229 .229
2699 3   .19003813 0 .705 .705
3192 3    .7619695 0 .819 .819
1226 1   -.6974397 0 .365 .365
1607 2  -.53420997 0 .454 .454
3172 3      .72391 0 .812 .812
2609 2   .10445177 0 .685 .685
1983 2   -.3496844 0  .54  .54
3392 3   1.1001801 0 .874 .874
3078 3    .6023574 0 .789 .789
 734 1   -.8496683 0 .236 .236
1976 2   -.3590761 0 .537 .537
2136 2  -.24302575 0 .575 .575
2604 2   .10296789 0 .682 .682
  17 1  -1.1979523 0 .006 .006
1433 2   -.6150438 0 .415 .415
1774 2    -.454978 0 .496 .496
3412 3   1.1337353 0 .879 .879
end
label values v190 wlth
Code:
pca x1-x74
predict comp1
rename comp1 v191

regr y v191 i.z        
drop if e(sample)!=1 
glcurve y , pvar(rank) glvar(Lorenz) sortvar(v191) replace by(z) split saving(v191_graph)

I also tried using a standardized wealth index but it is not working either.
Code:
egen sei=std(v191)
regr y sei i.z        
drop if e(sample)!=1 
glcurve y , pvar(rank) glvar(Lorenz) sortvar(sei) replace by(z) split saving(sei_graph)
I will really appreciate any insight into this-where I am going wrong or what does this mean? I can share my full PCA code and the related data, if needed.

Thanks in advance
Deepali
Array Array