[Update: there's a more thorough (and slightly different) analysis available now: http://www.cameronhuff.com/blog/court-of-appeal-statistics/index.html]
I've analysed 3000 Ontario Court of Appeal judgements from 1999 to 2014 using a program I wrote that extracts costs awards. Of the 3000 randomly selected cases that I supplied it was able to extract 733 costs awards with a high degree of confidence.
The average costs award was $12900. The median award was $8334.
Below is a plot of the awards (adjusted to 2014 dollars), sorted by year.
Note #1: I've excluded Oz Optics Limited v. Timbercon, Inc. from the graph because it was a $370k award (more than ten times the average) that made the graph hard to read.
Note #2: Many costs awards weren't able to be extracted. I've assumed that the discarded results are approximately the same as the successfully extracted results.
Note #3: Almost all awards include disbursements and tax. I haven't adjusted for the introduction of HST.