Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year of Issue | Description | Weight | Diameter | Thickness | Edge |
| --- | --- | --- | --- | --- | --- |
| 1976.0 | Round Nickel Token, Three Maple Leaves with Beads | 4.30grams | 21.9mm | 1.71mm | Plain |
| 1983.0 | Round Stainless Steel Token | 3.50grams | 21.1mm | 1.7mm | Plain |
| 1983.0 | Nickel Bonded Steel Token | 4.09grams | 21.2mm | 1.7mm | Plain |
| 1983.0 | Steel Token | 4.00grams | 21.1mm | 1.8mm | Plain |
| 1983.0 | Nickel Token | 4.07grams | 21.1mm | 1.8mm | Plain |
Question:
Which Thickness has a Year of Issue smaller than 1983?
Answer:
1.71mm