Stevenson and Wolfers provide a number of possible reasons why this occurred, including non-comparable data over time, and increasing income inequality in the US during this period.
Patients treated non-operatively, who survived 30 days after fracture, had a mortality rate over the following year comparable with those who had undergone surgery.
生存超过骨折后30天的非手术治疗患者，其随后一年的死亡率与手术治疗患者相当。
3
The Middle East accounts for less than 1% of world non-fuel exports, compared with 4% from Latin America (a region with a comparable population).