FG-460S What decade was it made in ?

Made in Taiwan, Republic of China. Serial number: 90228588. Rosewood sides and back My question is simple what year was this made ? I know the first digit should be the year but with just 9 to go on, I am confused as to what decade it was manufactured . 80's or 70's is my guess is likely 1989.

Thanks in advance. 

Angelo.