public static float calculateMarketChange(float start, float end) {
		int change = Integer.MAX_VALUE;
		int tries = 0;
		while (change > 10000 && tries++ < 4) {
			change = (int) (100 * ((Database.SUM_MARKET_PRICE_DATA.floorEntry(
					end).getValue()[6]) - Database.SUM_MARKET_PRICE_DATA
					.ceilingEntry(start).getValue()[6]) / (Database.SUM_MARKET_PRICE_DATA
					.ceilingEntry(start).getValue()[6]));
			start--;
			end++;
		}
		return change;
	}