How to export complete Google Analytics historical data?

This is a late reply but for the benefit of others, I would like to chime in here. The only way I have found is to use Google Analytics API but from experience this is extremely complicated for non-programmers. Here is a google anlaytics datawarehouse that will allow you extract data from any date in time and keep building history on a daily basis.

You can't (not with the free version of GA in any case). You can export aggregated reports (with up to 50 000 rows for standard reports or 200 000 rows for ad-hoc (not pre-calculated) reports via the API either by scripting yourself or using a tool like Next Analytics (the only programm from the Application Gallery I have used myself). But with 5 years of data you will at some point hit the courtesy limits for the Google API. And I'm not sure how helpful the exports are when you cannot get at the raw data.

Data Liberation from google may contanin updated info about this topic https://sites.google.com/a/dataliberation.org/www/google/analytics