public static String extractSqFt(String sourceText) {
		String[] lines = sourceText.split("\n");
		String result = "";
		for (int i = 0; i < lines.length; i++) {
			if (lines[i].contains("Grand Total Floor Area")) {
				// Grand Total Floor Area: 1,957 8 
				try {
					result = lines[i].split(" ")[4];
				} catch (ArrayIndexOutOfBoundsException e) {
					// 如果出现数组越界异常了，说明这个数值不在这一行，而是在当前的下一行
					result = lines[i + 1].trim();
				}
				break;
			}
		}
		return result;
	}