But there is also some coin that could drop more than 97% in just 24 hours 
http://www.cryptocoincharts.info/v2/pair/bdg/btc/poloniex/10-days
http://www.cryptocoincharts.info/v2/pair/bdg/btc/poloniex/10-days
and there are some that growover a 100% in 24 hours
however, trading is too risky
one day you'll hit a bad streak and lose everything..
Don't forget that if you get a -97% return today and a 100% profit tomorrow, you are still 94% down (100 -> 3 -> 6), instead of having no loss.
Exactly, it is just too risky for me.