I too have been playing over a year now.
However i have had better luck.
So far I have 9 mythics
I did eat my 2nd headliner
I play a lot, participate in raids, open a lot of packs.
Sometimes i save them for one big opening, but most of the time I am too impatient and open them up immediately.
I got like everybody else a mythic from birthday pack
I won my hoolies in a contest
I found them in legend pack from dubai 3
I found them in epics from Honolulu.
All very random.
Although they are strong they require a lot of DNA to level up and a lot of time!
Good luck all!