Which is the correct percentage decrease when decreasing from 421g to 347g?

Which is the correct percentage decrease when decreasing from 87g to 61g?

Which is the correct percentage increase when increasing from 50g to 57g?

Which is the correct percentage increase when increasing from $80 to $120?

Which is the correct percentage increase when increasing from €50 to €70?

Which is the correct percentage increase when increasing from $40 to $50?