The CW's four-show crossover between "Supergirl," "The Flash," "Arrow" and "DC's Legends of Tomorrow" was big, but the ratings were even bigger. Each of the four shows saw dramatic increases in viewership, and -- according to Deadline -- that boosted the whole network overall.

In its most-watched week in six years, The CW raked in an average of 2.3 million viewers, which is a 20% increase in total viewers from last year. Broken down, the network saw a 15% increase in adults 18-49 (0.7 vs. 0.6) as well as a 16% increase in adults 18-34 (0.6 vs. 0.5).

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"Supergirl" kicked off the crossover, which lead to an average of 2.36 million viewers that night, The CW's most-watched Monday night in seven years as well as their highest-rated Monday night in adults 18-49 (0.8/3) since October 2011. Additionally, it was the network's highest-rated Monday in adults 18-34 (0.7/3) since December 2012 and in men 18-49 (0.8/3) since January 2009.

The eighth episode of the season, “Medusa,” drew a 1.1 rating in the coveted 18-49 demo, meaning 1.1% of people in that age-bracket, with a television, watched the show. It also posted 3.5 million for first day viewers — its highest since total since leaving CBS and joining The CW.

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“The Flash” jumped a whopping +39% in total viewers between the crossover and its previous week, pulling in 4.15m viewers overall. Broken down, that’s a +50% increase in adults 18-34, +36% in adults 18-49 and +75% in men 18-34. Tuesday was up +37% in total viewers (2.576m), +60% in adults 18-34 (0.8/3) and +29% in adults 18-49 (0.9/3), which made that episode of “The Flash” The CW’s most watched Tuesday since February.

This crossover episode of “Arrow” was the biggest since last season’s crossover with “The Flash,” beating out its own season premiere and finale. With 3.55m viewers, the show rose 120% from the previous week's episode with a 1.3/5 rating in adults 18-49.

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"Legends of Tomorrow's" installment of “Invasion!” drew 3.39m viewers, with a 1.0/5 rating in the adults 18-34 demographic, while it tied for its second highest rating ever in adults 18-49 (a 1.2/4 rating). As such, the show saw its best ratings in the adults 18-49 demo since “Pilot Part 2,” its second episode, aired on January 28. What’s more, “Legends” achieved its highest rated episode ever in men 18-34 (1.2/6) and tied for its best rating in men 18-49 (1.4/5). Thanks to “Invasion!”, “Legends” was up a whopping +80% in overall viewership and pushed The CW to its most-watched Thursday night since October 2012.

Starring Melissa Benoist as the Girl of Steel, “Supergirl” airs Mondays at 8 pm ET/PT on The CW. The network is also home to Grant Gustin as the Scarlet Speedster in “The Flash,” airing Tuesdays at 8 pm ET/PT, Stephen Amell as the Emerald Archer in “Arrow,” airing Wednesdays at 8 pm ET/PT and Arthur Darvill, Brandon Routh and Caity Lotz in “DC’s Legends of Tomorrow,” airing Thursdays at 8 pm ET/PT.