We will not be able to find a stable number in the crypto market and I advise you to give up that plan.
This is because a volatile market will never give investors a stable return. It can make us say 15% of today's property value, but tomorrow it will make us lose more than 30%.

I agree in a fact that there is no stable return in cryptocurrency and it actually depends on how the market runs. Sometimes we lose, sometimes we win and that also depends on your trading strategy plus applying your experiences will also give you better understanding where to sell or buy it back. Gaining and loosing can be controlled if you are a day trader and using the stop limit / stop loss tools properly. Controlling your emotions is always a must.