Hi SALTYDOG. It is not possible to answer that question. As with any mechanical device, it could last the lifetime of the vehicle or fail today. There is no average lifespan to base an answer.
As an example: My father factory ordered a 1990 Lincoln Town Car. It was sold to a neighbor in 2007. It is still running perfectly, with the original fuel pump and over 225,000 miles today. On the other hand, a defective fuel pump could fail in the first year of ownership.
Your fuel pump is cooled by the fuel so try to keep the tank at 1/4 full or above and it will last longer. I have not heard of a typical replacement time frame or mileage, but it will likely be a long time. I replaced a fuel pump in a 1991 Grand Marquis with less than 100,000 miles.