I would guess late 90's to early 2000's model. But there should be a serial/model number tag that you can research and find out.
A tag behind the seat should have the 4 digit manufacture date as well as the model number.
C&P:
In the 90's, Murray was using what is called a "Julian date" coding system. That is, the first number is the last digit of the year, e.g. for the year 1994 the first digit of the date code is a "4". The next 3 digits is the day of the year from 000 to 365 (or 366).