How can one approximate prior to traveling the percentage of products in local shops with an English translation? [closed]

I don't think such a list exists as such.
Also this will be very specific to the area / country you are travelling to.

My impression is that there are certain everyday items that you want to have during your travels that make you feel more confortable.

Make a list of these items:

• Item name (Brand)
  • alternative brands that are similar in nature
• Basic name (to be used for translations)
  • which describes what it is
• where it can be bought
  • type of shop (Grocery, Pharmacy etc.)

For each item collect the package wraping

• that may contain a picture and description
  • something that others may recognize easily through the picture

Make a list of the countries / Cities you are going to visit

• get a translation of the
  • Basic name
  • type of shop
• look for shops in the Internet of the same type or Brand
  • they often have search capabilities
    • search for Brand, english or local Basic name
  • note the name of the shop where you have found something
    • peaple may recognize the shop name and understand what your looking for
      • Lidl, Aldi --> Grocery Store

Compile this information into a A5 binder that contains plastic* envelopes

• store the basic information for each product
  • with the original packaging
• use this to show people
  • in a Hotel / Pension
    • they will help you find the right type of shop
  • in the shop
    • they may recognize the packaging and help you further

* _{I know and understand that plastic is a no, no - but on a windy, rainy day more practical}

The best weapons against the language barrier are pictures

• and will definitely be more effective than sign language

Properly prepared, just pointing to the picture and translated name of product and shop type will probably get your very far, very swiftly.