However, Hamilton remains unconcerned by his run of results.
He told reporters: "At the moment, knowing we have a lot of races ahead of us, it's not concerning me too much."
"Of course if it was later on in the season and we were where we were it would be a little bit different.
"But in one sense it's comforting for me to know that I feel like I've done my optimum up until now, but there's still room for improvement. As a team also it's in some ways positive for us to know that we can still improve. If we were perfect then it wouldn't be fun for the rest of the year."
Hamilton will be racing for the first time at Austria's Red Bull Ring, which hasn't hosted a grand prix since 2002.