No, it needs a little work. It is not natural. 'something has not changed' is expressed as 'nothing has changed'. 'Nothing has changed during the past 70 years', or 'After 70 years, nothing has changed' are possibilities. Meaning is slightly different between the two: the first stresses nothing has changed DURING that period of 70 years, the second simply says 70 years have elapsed and things remain the same.

Thank you.

In all of the seventy years, not a thing changed.