列表法和作图法是常用的数据处理方法。下表是氯化钠和硝酸钾在不同温度下的溶解度，两种固体物质的溶解度曲线如图所示。请根据图表回答：  

                                                                                                                                                                                                                               

温度/℃		20	30	40	50	60	70	80
溶解度/g	NaCl	36.0	36.3	36.6	37.0	37.3	37.8	38.4
	KNO3	31.6	45.5	63.9	85.5	110	138	169