BA project

In a state with 3,200,000 PIF (Policies in Force), 38% of them are preferred and 62% are non-preferred. If we are only selling preferred policies (assume preferred is growing at a rate of 9% annually), how many years will it take before we have more preferred policies than non-preferred policies? (Note: Assume that our non-preferred book of business does not grow or shrink.) I need the answer ASAP