Has banning ivory lessened the amount/percentage of elephants killed each year or has the ban simply made ivory more valuable and thus worsened the situation?

From what I've read, it "seems" that less Elephants are being killed for ivory now. It's made the price of Ivory skyrocket so black markets will continue to thrive and pay off the right people to keep it quiet. So, it's really hard to find the actual truth to the matter.