Insolation by country?

[Maven]

I'm doing a regression analysis on several European countries and I want one of my variables to represent average insolation (or solar radiation) per country. However, I cannot find these kind of data in any website: I can only find maps that give you the insolation for a given point.

 

Does someone know a website that provides this kind of data? Or could someone propose me a way to calculate this insolation per country?

 

Thank you in advance.

[doG]

I'm doing a regression analysis on several European countries and I want one of my variables to represent average insolation (or solar radiation) per country. However, I cannot find these kind of data in any website: I can only find maps that give you the insolation for a given point.

 

Does someone know a website that provides this kind of data? Or could someone propose me a way to calculate this insolation per country?

 

Thank you in advance.

[swansont]

You might not find a number for individual countries because, as doG's map shows, insolation varies with latitude (among other variables). It's given as location-dependent because it is.