Dot chart showing percentage of absolute errors in an experiment

Reproduced from Cleveland, W.S. & Mcgill, R. 1984. Graphical Perception - Theory, Experimentation, and Application to the Development of Graphical Methods. Journal of the American Statistical Association, 79, (387) 531-554.
The dot chart above was used to display grouped data values proportions, expressed as percentages. The dot chart shows percentage of large absolute errors on different images with grouping by experiment. The groups are indicated on the chart by a wider gap between the type names on the left (see Cleveland and McGill 1984 for type reference), i.e. there were five types in the first group and two types in the second group. Higher percentages of errors are associated with types with dots plotted more to the right.