I guess it would depend on if you want it measured by months,weeks,days,minutes,seconds,etc.
Why don't you post a question that is more specific?
Hope this helps...o.o
6 percent of 1000 is 60 - whether now, 20 years ago or 20 years from now.
20 years
20 years
it lives 20 to 30 years
20 years
20 years
Because more disappearances has happened in the last 20 years
20 years
200 trillion kilometers.
20 decades = 2 centuries or 20*10 = 200 years
20 years older
5-20 years.