2010 - Iron Man 2
2011 - Thor 1, Captain America 1, X-Men: First Class
2012 - Avengers 1, Dark Knight Rises, Amazing Spider-Man 1
2013 - Iron Man 3, Thor 2, Man of Steel, The Wolverine
2014 - Winter Soldier, Guardians of the Galaxy, Amazing Spider-Man 2, Days of Future Past, Big Hero 6
2015 - Age of Ultron, Ant Man
2016 - Deadpool, Batman v. Superman, Civil War, X-Men: Apocalypse, Suicide Squad, Doctor Strange
2017 - Logan, Guardians of the Galaxy 2, Wonder Woman, Spider-Man: Homecoming, Thor 3, Justice League
2018 - Black Panther, Deadpool 2, Venom, Incredibles 2, Aquaman, Ant-Man and the Wasp, Infinity War.
2019 (so far) - Captain Marvel, Shazam, Avengers 4, Wonder Woman 2, Dark Phoenix, Spider-Man: Homecoming 2
Aside from 2015, which was surprisingly quiet. Just about every year has gone from 3 Superhero movies a year to 7. SEVEN.
That's an average of at least 1 superhero movie every 2 months.
So, yeah. I think referring to the 2010s as the Decade of Superheroes is pretty accurate.