The Drake equation is:
N = R* . fp . ne . fl . fi . fc . L
N = the number of civilizations in our galaxy with which radio-communication might be possible (i.e. which are on our current past light cone);
R* = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space
so fp seems to be 1,
ne seems to be what 1 in 10 maybe?
So hopefully N is non-zero - we're getting closer...