I found some data for the UK: each year, ~2.7M cars are sold [1], and ~70k stolen [2]. In the same time, 3.5M bikes are sold [3], and 400k stolen [4]. In France, there are ~1.8M cars sold [7] vs ~110k cars stolen each year [5]; 2.8M bikes sold [7] vs. 400k bikes stolen [6]. Meanwhile, in Montreal, half of all active cyclists have their bike stolen [8].
[1]: http://www.bbc.com/news/business-38516247
[2]: http://www.telegraph.co.uk/finance/newsbysector/transport/11558743/Number-of-cars-stolen-in-the-UK-falls-to-48-year-low.html
[3]: http://www.cyclinguk.org/resources/cycling-uk-cycling-statistics#How many people cycle and how often?
[4]: http://www.cyclist.co.uk/news/412/bicycle-crime-statistics
[5]: http://www.lefigaro.fr/automobile/2015/10/29/30002-20151029ARTFIG00145-en-france-300-voitures-sont-volees-chaque-jour.php
[6]: http://www.veloperdu.fr/statistiques
[7]: http://transports.blog.lemonde.fr/2014/04/07/10-chiffres-meconnus-sur-leconomie-florissante-du-velo/
[8]: https://www.citylab.com/transportation/2014/04/these-8-depressing-bike-theft-statistics-show-just-how-bad-problem/8890/
Lived in Montreal off and on over the years, mostly summer. 4 bikes stolen, the first two were pretty nice road bikes; lesson learned. Now I just pick up a beater off of Craigslist along with a thick chain link lock.
If you leave a bike out over night there's a good chance it will be gone in the morning.