The Finn established himself as Sebastian Vettel's main title threat early on, as Lotus's excellent tyre management helped him win in Australia and regularly finish on the podium.
Raikkonen held second in the standings until Spain, at which point he was only four points shy of Vettel.
But the Lotus driver has been unable to keep up his consistent form, and his cause was not helped by a collision with Sergio Perez in Monaco and then tyre struggles in Canada.
The extent of Raikkonen's woes is highlighted by his points tally from the last four races, where he has not only been outscored by Fernando Alonso, Nico Rosberg and Mark Webber, but he has also lost a whopping 41 points to Vettel in the standings.
From breathing hard down the neck of Vettel early on, Raikkonen is now 44 points adrift of his Red Bull rival.
Sebastian Vettel 80
Fernando Alonso 53
Nico Rosberg 45
Mark Webber 43
Kimi Raikkonen 39
Lewis Hamilton 37
With a gulf now opening up between Raikkonen and Vettel, Lotus is well aware that it will need to start producing race wins if it is to close that gap quickly enough.
Raikkonen's laidback attitude off track may give the impression that he is as relaxed on it when it comes to results, but he is adamant Lotus is giving nothing less than 100 per cent to try to win more races.
"We always try and win," said Raikkonen. "It is not going to just change our race result if we try to do something different.
"We have mostly had the speed, and we will keep trying, but there is not just a way to be more aggressive and you have a better chance. We always try that.
"It has just not been possible. We have been up there and been OK. Monaco was not as good as we hoped. But there is still a long way to go."
Lotus boss Eric Boullier told AUTOSPORT in Montreal that he expected his team to be back at the front at the British Grand Prix, thanks to a speed boost from car updates and F1's return to more normal high-speed tracks.
"We have some good developments coming for Silverstone so that should help us keep up and close the gap to the leader," said Boullier. "With normal tracks we should be able to get the best out of our car."
The statistics from the last few races have highlighted, however, how essential it is for Raikkonen to do exactly that, just as his strong form earlier in the year has left rivals not ready to write him off just yet.
Red Bull boss Christian Horner said: "I think ultimately you cannot write off Kimi.
"If he can put together a run of race results, just as Lewis, or Mark could, he can get himself back in the championship hunt."
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- Sebastian Vettel
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- Nico Rosberg
- Mark Webber
- Fernando Alonso