This highly effective little graphic comes from a white paper produced by Roger Geller. The key to bike ridership is not converting the "Interested but Concerned" into "Enthused" or "Fearless." Changing people is far more difficult than changing the infrastructure (unless you are the City of Dallas).
Instead, you have to tap into that population base. But why?
For one, despite the various regional geographies and mindsets we might personally identify with, these percentages are pretty consistent no matter where the question is posed. Portland, Dallas, or Amsterdam. The difference is how amenable the infrastructure is.
Is far safer, cheaper (for city and individual), more spatially & energy efficient, and healthier than this:
How much longer would you like your income heading towards these things? At some point, the choice will no longer be yours.