Even including the few graphs going back to the 1850's, these are such a short
time span that it doesn't take into account what has happened previously, to compare and look for trends
over many
thousands of years.
Only one
of the past «Big Five» mass extinctions (the dinosaur extinction event at the end
of the Cretaceous) is thought to have occurred as rapidly as would be the case if currently observed extinctions rates were to continue at their present high rate (Alvarez et al., 1980; Barnosky et al., 2011; Robertson et al., 2004; Schulte et al., 2010), but the minimal
span of time over which past mass extinctions actually took place is impossible to determine, because geological dating typically has error bars
of tens
of thousands to hundreds
of thousands of years.