My guess is it is from approximately 1950-2005. I base this on a time frame for 27" tires (need to factor in time for the side walls to deteriorate), which I'm guessing an '81 Miyata sold in the USA wore. Since there are several other variables involved, such as, they could be 700c or another sized tire, the date range could be pushed even further back.

Help us out with more clues!