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It is similar in the US (no, really! since the 1990s); it's going down, but no one really knows why although a number of theories are espoused.
I think the lead in petrol hypothesis a bit weak, and no doubt the real reason is a blend of several complex issues that I am ignorant of but my own personal theory is the 'equalisation' of everyone: we don't have everything we want but we are more than comfortable; I am over-generalising grossly but everyone has a 'flash' TV, everyone has a smart phone and everyone has access to the Internet and there are now so many TV channels. Added to which barely anybody in the West is really in poverty or starving so what happens? We can't be bothered, we don't 'need' to steal; the only ones committing crime are the sickos who always will, no matter what, or those from a not-so-developed country/culture that they haven't been 'equalised' yet.