Correlation, causation, and conclusions
While it isn't a bad thing, in and of itself, to attempt to collect data, and make sense of it, there's bit of a problem with collecting data, finding that it is inadequate to draw conclusions from, and then...draw conclusions from it.
Botnets are decreasing in abolute terms? Interesting. Botnets decreasing in relationship to aggregating personal computers numbers with devices/platforms that may, or may not have relevance to botnets? What does that mean? Anything?
The zero day conclusions: I don't have complete data, yeah, there's a bunch of scary zero day things, and I don't have any way to figure out how "dangerous" they are or how exposed people are to them, but hey, if I increase the pool of potentially impacted people, the ratio goes down. Yay, we're safer?
If we add in the human population to the bird population, and then calculate the ratio of creatures dying from avian flu on an annual basis...are humans getting safer? Or is the question so unrelated to the available data that attempting to answer the question with the data silly?