Findings
Looking at the bubble chart one will immediately notice that there is a bigger bubble at the centre, that is 24, a serial drama which stars Kiefer Sutherland as Jack Bauer, focusing on the efforts of the fictional Counter Terrorist Unit, and on their efforts to protect USA from the terrorism plots. This Terrorist Unit collaborates both in the second and the eighth season with the NSA.
Generally speaking there are two different groups, one colored in blue-shades, located at the border of this cloud, and the other one in red-shades, at the centre. The first one is bigger and contains all the series in whitch NSA is mentioned less than 30 times. On the other hand the red group show the significant basin of the TV series in our analysis. The light blue bubbles are not so important and probably the NSA isn't a key subject of these TV series. The anchor group between the red bubbles and the blue ones is violet and it is heterogeneous since there are series that mention NSA in more than 25 episodes, like the famous drama NCIS, and others that mention the Agency only in 6 episodes, like The Good Wife.