What are the top five causes of the bicycle tyre flats you experience?

I've had a puncture on each of my last four rides.  Which made me wonder what causes the most bicycle tire punctures in various parts of the world.

Please rank the following from 1 to 6.
1 is the cause of most of the bicycle tire punctures you have experienced.
5 is the cause of least of the bicycle tire punctures you have experienced.

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* 1. Please rank the following from 1 to 6.
1 is the cause of most of the bicycle tire punctures you have experienced.
5 is the cause of least of the bicycle tire punctures you have experienced.

If something else is the main cause of bicycle tire punctures you have experienced, please type that into the text box below.

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* 2. If something else is the main cause of bicycle tire punctures you have experienced, please type that into the text box below.

Where do you live?:

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* 3. Where do you live?:

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