What is the Key percentage?

In Odds Universal, Key is the sum of implied probabilities across a market. For 1.60 and 2.20 it is about 107.95%. Our reference tables use pairs near 108%, including 1.50/2.40, 1.55/2.30, 1.60/2.20, 1.65/2.10, 1.70/2.00, 1.75/1.95, 1.80/1.90 and 1.85/1.85. They are not all exactly 108%.