No worries. It really doesn't detract from the point. A 40% increase in that span is still significant.
I'd hesitate to claim that this rate of change is unprecedented, though. The resolution of much of the historical data is on the order of thousands or tens of thousands of years, so we wouldn't be able to detect CO2 release rates faster than that. I wish we could. The geological history was active enough early on that it would give some nice insights into the sensitivities of the varying forcings.