Exact Time Period of 'The Americans'

So obviously 'The Americans' is set in the '80s but I was curious if any other viewers who lived during the Cold War era and/or who have studied the history of that time period can tell me an approximate year for each season? Unlike other period shows, i.e. Mad Men, 'The Americans' seems much less concerned with telling viewers the exact year that events are taking place during. Based on my observations, each season covers about a year of time (Philip mentions in season four that he's been working Martha for three years).

FYI I'm on season 4, episode 8 ("The Magic of David Copperfield"), so please, no spoilers from after that. Thanks comrades! lol