Damn it! I should have asked that earlier
Now its to late. xD
Then i have to go on, search and search and search.
But thx a lot. 
Anyways, you'll have to search a lot. Because 20 destinations is usually not enough.
in the page of your base airport, there is a graph that summarizes the demand, split between "domestic"; "international"; "intl. long haul".
domestic is everything in the same country, international is everything else in a radius of 2500NM, intl. long haul is everything else. If both three values are similar, it's not a big help, but if they are strongly different, it helps a lot. For example, I'm based in Detroit, with 92% domestic demand. I can check routes to other countries, but I
know the bulk of my routes will be within the USA.