But if the gains have been worth just 1% a year, over the past 30 years that would cumulate to a gain of 35%. And combining that with the CBO estimate of a gain of about 50% would imply that the real income of the median household is up nearly 2.5% a year over the past 30 years.
没人知道这些产品创新和改进给我们增加了多少福利。但假设这些收益只相当于每年1%，过去三十年累计下来也能造成35%的增长。将这个数字与CBO所测算的50%左右的收益相加，意味着实际中位家庭收入在过去30年的年增长率接近2.5%。