There are two factors contributing to the ratio. One is the amount of SBD in circulation (which has been declining, and will probably decline consistently from here on out given the size of the potato fund) and the other is the price of STEEM. If the price of STEEM declines then the ratio will go back up. That being said, if the amount of SBD in circulation decreases enough, then the ratio will go down regardless of the STEEM price. At the current rate of decline, this may take some time, though the rate is increasing as potato accumulates more funds.