Chevrolet sold 2,629 Sparks in 2015.
http://us7.campaign-archive1.com/?u=994 ... 78867c2845
There were 5,163 PEV cars sold in California in 2015.
Since the Spark is only sold in California, Oregon and Maryland (and anywhere someone is brave enough to buy one and ship it in to), you can bet the bulk of the Sparks sold were sold in California.
The Spark might have a higher adoption rate in Oregon than other states because in 2015 there was no state rebate for the purchase of a PEV (only a small rebate for purchase of an EVSE) nor is there an HOV sticker available and the lower price of the Spark, compared to other PEVs, might have tipped it a bit.
This for a car with virtually no advertising or roll-out drama and supply-caused shortages. Not bad, eh?
Anecdotally, in 2015 here in Oregon the dealers repeatedly sold out of cars and then had to wait until they got their next shipment, indicating that popularity is not the problem, supply is. I took my Spark to an EV show with a dealer brochure and they said they had 7 people - in a town of less than 20,000, green and crunchy though Ashland is - show up at the dealership asking about test drives. That was in September, by that point they were sold out and only got another shipment in in January.
I think the Spark was both a compliance car and a test run for PEVs, we will see what lessons they learned when the do the US rollout of the Bolt.