(As usual, all information comes from my own timelines, but some of these are approximated guesses. Also, I've used chronological time, rather than the "soap-opera" time that the show employs.)
1973 - The Impala is sitting in a used car lot in Lawrence, Kansas.
1979 - Dean is 3 months old and is the cutest!
1983 - Mary is coming to the end of her pregnancy with Sam, and is most likely looking forward to seeing the little guy.
2006 - Sometime near the end of April, Dean gets electrocuted causing Sam to take over most of the driving while he desperately tries to find a way to save his brother's broken heart.
2007 - Dean was possibly just attacked by a Djinn and strung up in a warehouse. Luckily, Sam is looking for him.
2008 - Dean and Sam may be torturing demons in an effort to find Lilith and save Dean's soul.
2009 - Sam is recovering after being attacked by a ghoul disguised as the younger brother that he never knew he had.
2010 - The boys try to collect the rings of the four horsemen. Meanwhile, Sam contemplates just what he might have to do in order to save the world.
2011 - The Impala is under a tarp in Lisa's garage, while Dean drives a more practical truck to work every day. Sam's soul is trapped in the cage. Sam's body is hunting with a resurrected Samuel Campbell, and they may have just started tracking some Djinn that have a specific victim in mind...
2012 - It is around this time when Sam kills monster-possessed Samuel Campbell, and sadly, monster-possessed Bobby kills Rufus Turner.
2013 - An old friend, Annie, dies in a haunted mansion. Dean and Sam see Bobby's ghost for the first time since his death months before. The Impala, meanwhile, is sitting under a tarp in an undisclosed location, in order to keep it safe from the leviathans.
2014 - Sam, still living at motel in Kermit, TX, has started dating Amelia, a local vet. Meanwhile, Dean wanders through Purgatory, hopefully, at this point, with Castiel and Benny at his side. The Impala is in Sam's care.
2015 - ??