Methodology: the TVI tracks the recency- and condition-weighted average value of a catalogued tiki mug, expressed as an index rebased to 100 on the first day of available sales data. In other words, a TVI of 120 means the typical mug is worth 20% more than at the index's start. The average mug value shown alongside is that same figure in dollars. Sub-indices show the average mug value within each category. Figures are estimates derived from historical sale data and are not guarantees of sale price.