We want delinquency rate by credit score band: below 620, 620 to 679, 680 to 739, and 740 and above. Six customers have scores of 600, 620, 650, 680, 700 and 760, and the ones at 600, 620 and 680 are delinquent. How would you do this in pandas, and what is the delinquency rate in each band?

我们要按信用分分段看逾期率，分成620以下、620到679、680到739、740及以上四段。六个客户的分数是600、620、650、680、700、760，其中600、620、680这三个人逾期了。你用pandas怎么做？每段逾期率是多少？