Hi Keith;

>1.  Does the USDA data base report on n-3 and n-6 fats?

http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl

1 oz (14 halves) = 28.350 grams

Fatty acids, total polyunsaturated  g 13.374
18:2 undifferentiated  g 10.799
18:3 undifferentiated  g 2.574
18:4  g 0.000
20:2 n-6 c,c  g 0.000
20:3 undifferentiated  g 0.000
20:4 undifferentiated  g 0.000
20:5 n-3  g 0.000
22:5 n-3  g 0.000
22:6 n-3  g 0.000

1 oz (6-8 kernels) = 28.350 grams

Fatty acids, total monounsaturated  g 6.525
16:1 undifferentiated  g 0.092
18:1 undifferentiated  g 6.345
20:1  g 0.018
22:1 undifferentiated  g 0.000
Fatty acids, total polyunsaturated  g 6.841
18:2 undifferentiated  g 6.749
18:3 undifferentiated  g 0.018
18:4  g 0.000
20:4 undifferentiated  g 0.000
20:5 n-3  g 0.000
22:5 n-3  g 0.000
22:6 n-3  g 0.000

>2.  If it does, how do I derive that ratio from its analyses?

From http://www.fish-foundation.org.uk/omega-3.htm this appears to be helpful;

THE OMEGA-6 POLYUNSATURATES
LINOLEIC ACID(18:2,W-6)
from vegetable oils such as sunflower, sesame, safflower etc

GAMMA-LINOLENIC ACID(18:3,W-6)
from evening primrose oil, borage and  blackcurrantseed oils

ALPHA-LINOLENIC ACID (18:3,W-3)
( a short chain omega-3)
from linseed and rapeseed oils

ARACHIDONIC ACID (20:4,W-6)
found in small amounts in meat, eggs

EICOSAPENTAENOIC ACID (20:5, W-3)
( a long chain omega-3)
only significant diet source is oil-rich fish

DOCOSAHEXAENOIC ACID (22:6,W-3)
(a long chain omega-3)
major source is  oil-rich fish; small amounts in meats & eggs.

Marilyn