For individual swim meets you can see the results posted (at the meet) or online afterwards. This gives you a comparison between your previous best and your latest swim – only a snapshot of your progress.
The best way to get a long-term picture of your progress (hopefully improvement) over time is to use the new MyTogs app provided by Swimming NZ. This gives a much better view of your progress over time.
Result for Swimming New Zealand meet are posted to the database, so your times are already available for you.