Well, I really paraphrased the crap out of it. It was more along the lines of that Sonic rejuvenated system sales. We don't have a month to month resolution here, so we don't know if the sales were really lagging/had a sharp drop off until Sonic was released, etc.
Some interesting things; the famicom took a drastic drop in sales for 87 (the year the PCE was released) and kind of slow decay from there. The introduction of the SFC and both decline of the MD and PCE forever onwards. While SFC took a nose drive in '94 and kept on diving. That slight sustain for MD for 1994 is strange. What softs could have produced that? The introduction of the n64 and the drop in saturn sales afterwards.
Also, I graphed the sales data from the other pic to see how it would look:
