The different application styles and shades can give a production period but not an absolute time line. A more accurate time line could be determined by the original hang tag or sticker & corresponding glaze color and thickness of the applied glaze. The earlier pieces have a heavier glaze and usually have more variation in colors.The later production has a more constant color specifically the green glaze.Each Glaze color will start with the earlier colors moving up to the later colors where applicable. As an example the Mocha glaze was fairly consistant over the production years.
The mold mark is another time line indicator by the style of the mark. The different styles can be found in the Marks,Tags & Stickers section