San Francisco: 170
New York: 96
London: 90
Boston: 38
Berlin: 34
That is debatable and depends largely on a definition. My viewpoint is that a large portion of the companies in the current VC-inspired "tech" world are merely applying tech and not really developing it. For every company like Datastax there's a dozen of companies which are just applying tech solutions (packaged and sold by other companies) to a specific business/consumer problem.
Or, to put it in other terms, if the job offer does not say "Msc/PhD in X preferred" (where X is the job, like distributed systems, deep learning etc.), then it's likely not quite a "real tech" job.
That might or might not be a bad thing. It means you're more likely to be working for a real company, with a real business model, rather than some freak kept above by advertising and VC misallocation.
For example, in the UK, there's little real tech companies and most developer roles are confined to non-tech support roles in other economy sectors (finance, retail etc.).