Total number of hashes performed for bitcoin purposes? I would like to estimate the total number of hashes (double SHA-256) that have been performed for bitcoin purposes.

As an estimate, I downloaded mining stats, massaged the numbers (assuming the rate shown is for the period ending at the date indicated and starting at the date before), came to 201⋅1024 hashes (equivalently 287.38 or 288.38 SHA-256) on Oct 28, 2017.
[update: 517⋅1024 hashes that is 288.74 or 289.74 SHA-256 by May 4, 2018].

Did I goof badly in that estimation of the hashes used for mining?

What other comparably non-negligible number of hashes is performed for bitcoin purposes, and how can that be estimated?

Clarifying: I'm looking only for things that represent a sizable fraction of the number of hashes spent for mining, say at least 0.5%; I'm totally willing to ignore the rest.
Assuming the numbers in the link are correct, then I think this would be right.

I got the same result by multiplying every entry by (1,000,000,000,000 * 3600 * 24 * 2) and adding them up. Came out to 2.008E^26.

But the total number of hashes is much higher. Every block in the blockchain is hashed by every client, every transaction is created using several hashes, etc, etc.