Exponential growth in world EV sales continues

Inside EVs have published their latest estimates of US  and world EV/PHEV sales.  (Their basic data; my seasonal adjustment, my trend estimates and my estimate for global car sales in 2017) For the first time I've plotted the chart on a log scale.  A log scale is better for showing things that are growing exponentially.  In this case it shows (roughly) a rising straight line, implying that in absolute terms, the rise in the percentage of EVs sold is accelerating.

The year-on-year growth rate continues to pick up.  This is before Tesla 3 or Nissan Leaf sales have got going.  At the current growth rate (65%), EVs/PHEVs will make up 3.6% of all new car sales this time next year.  With Leaf and Model 3 sales likely to explode in 2018, my guess is that that percentage could be even higher.  From 0.4% of the world market at the beginning of 2014, to 4% at the end of 2018 .... if the growth rate (i.e., the straight line in the chart above) continues, EVs and PHEVs will be 40% of the world car market by the end of 2023, and close to 100% not long after.  What price oil?