If you notice the ranking is not consecutive with the use of the RANK function; that is because the RANK function ranks records of the result-set sequentially starting from 1. When it finds a tie it assigns the same rank to the all the records in the tie, but still keeps incrementing the record counter so the next record will get a new rank which would be (previous rank + no of records in the current tie + 1) .
not plausible; not having the appearance of truth or credibility: an implausible alibi. Origin of implausible. 1595-1605.
If such a span is 200 years, that means that an average of 50 years time passed from birth of a person to that person giving birth to the person in line. Implausible. If the total span is 40 years, that means ten year olds were having babies (on average). Also implausible.