英语翻译

英语翻译
Those who begin their careers in a bust are less footloose than their boom-time equivalents.Ms Schoar and Mr Zuo find that the average recession-scarred chief executive is more likely to have risen through the ranks of a firm than the norm,and is less likely to have switched employers or jumped from one industry to another.
参考译文：相比那些在经济繁荣期间开始工作的同行,在萧条期间开创职业生涯的人显得更稳定.肖尔女士和 佐先生发现一般经历过经济衰退的首席执行官有更大的可能是从公司的底层一步步爬上来的,也不大可能跳槽或变换所从事的行业.
Ms Schoar and Mr Zuo find that the average recession-scarred chief executive is more likely to have risen through the ranks of a firm than the norm,
3.the average recession-scarred是什么含义?（这个看翻译好像是经济萧条 但是这个average不知道从何理解 recession-scarred不景气的伤痕么.)4.the ranks of a firm than the norm是什么含义?(看翻译是从公司的底层一步步爬上来的但是觉得难理解）