From the standard normal distribution table (Z), it is found that P(Z<0.50)=0.6915, P(Z<1.00)=0.8413, P(Z<1.50)=0.9332, P(Z<1.96)=0.9750 and P(Z<2.00)=0.9772. If the results of the extraction of raw materials for each unit to make essential oils (X) have a normal distribution with an average value of 20 grams and a standard deviation of 5 grams. If 2.5% of the raw material yield is taken, which has the most extraction results and will be specially packaged, what is the lowest limit value for the raw material to be specially packaged?