'(num2 - num1) / num1 * 100'

def _get_augment_rate(self, data):

    result = '+0.0'
    if ((len(data) == 2) and (float(data[0]) != 0)):
        result = ('%+.3f%%' % (((float(data[1]) - float(data[0])) / float(data[0])) * 100))
    return result
