Holy shit, even today only 1 in 10,000 articles are retracted for fraud.
I am assuming these retracted articles are a tiny fraction of the actual number/% of articles with fraud, and such a tiny fraction as to not give reliable evidence for the proportion increasing; so the graph's data isn't particularly useful.
From Gene Expression by Razib Khan who some of you may also know from the old gnxp site or perhaps from his BHTV debate with Eliezer.
Link to original post.