I'm just passing on info I read
http://m.ign.com/wikis/the-legend-of-zelda-breath-of-the-wild/100_Percent_Completion_Checklist
The only way you can see what your total completion progress is at is by beating the Main Quest
Walkthrough. After defeating the final boss you will be allowed to load the last auto-save before the end, and the save file will have a star that denotes you have completed the game on that save file.
In this save file, you can look at your map on the
Sheikah Slate, and in the bottom left corner alongside the time of day and temperature is a new percentage out of 100% that tracks your total completion. However, this completion percentage
ONLY applies to what has been discovered on the map. There is no overall completion percentage for other activities in the game - but you'll also be able to track how many Main Quests,
Side Quests, and Shrine Quests you have completed out of the total amount in your Adventure Log.