2015: in two years https://fortune.com/2015/12/21/elon-musk-interview/
2016: in a year https://www.businessinsider.com/elon-musk-autonomous-tesla-d...
2017: in two years https://electrek.co/2017/12/08/elon-musk-tesla-self-driving-...
2018: in a year https://electrek.co/2018/03/11/tesla-ceo-elon-musk-self-driv...
2019: in a year https://www.wired.com/story/elon-musk-tesla-full-self-drivin...