Retention Metrics for Health and Fitness Apps

I am trying to research more on retention metrics for health and fitness apps and I find no reliable data. May be the community can help me here. Summary of my findings: 1) Myfitnesspal D30 rates are in lower single digits. (from someone I know) 2) Most of the apps' D1 retention numbers for new users are < 20% (as per an Andrew chen blog)

If you guys have any insight on this, please let me know