Oh no! Not another perfect pitch thread!
Technically speaking, there's is no "degree" to perfect pitch. If you can't tell all the notes, you don't have perfect pitch. Hence the term "perfect".
However, studies did show perfect pitch to lose it's accuracy over the years as one age. My perfect pitch went out about half a semi-tone (quarter tone) last time I tried and shocked me - had to "re-tune" my ears at that time. Must be my age...
Good of you to have perfect pitch. But we perfect pitchers should be careful not to be too proud. Like any skills, if it's not put into good use, it's as good as useless (and as somebody said in another perfect pitch thread...it's just another party-trick).
And yes, I believe it can be trained to a certain extent. But it's not crucial if one doesn't have it. Relative pitching is still the most important (and easily acquired).