Non F Body question - 12 volt outlet

[Formula413]

The 12V power outlet in my Civic is only on with the ignition switch in accessory or on, and I want to wire it to be on all the time, to power phone and GPS chargers. What would be a good circuit to tap into? It's rated for 10 amps, I'd like to at least keep that or up it to 15. The first thing that came to mind is the constant power wire to the radio. Any other suggestions? I believe in an F Bucket it shares the same circuit as the OBD-II port, which is also near the outlet.