The Finn has been far more consistent this year, although thus far he has failed to win a race, logging second places in Bahrain, China and Spain and suffering a late puncture in Baku while in the lead.
"I think this year I have been meeting more or less my targets with the performance for the beginning of the year," said Bottas.
"I think I've been able to really continue good performances from the end of last year.
"And there have been no weekends that I have been way off the pace, like there were a few last year. So I feel I have learned from those, and need to continue my development.
"There are never things that you can't learn more, so I still hope I keep improving. I think there's been quite mixed races, and the end results haven't been really I feel sometimes quite there, that I