Average Business Expenditure broken down into Core / Non Core Activities (definition in desc)

I am working on a project that needs to know one number - the percentage of business expenditure that is made up by non-core activity costs.

------

Definitions

------

*Non-Core Activities - Supporting activities that a business must complete but do not contribute directly to the customer offering

*Core Activities - Activities that contribute directly to a customer offering.

For example, A coffee shop's core activities are making coffee, serving customers, preparing food. Non-core activities include payroll, tax, staff rosters, recruiting, etc.

------

Requirements

------

Please note - This number MUST BE BASED ON A RELIABLE SOURCE. References are required. A reliable source would include a published academic paper, professional services firm (such as PwC, EY or a lower tier firm), A government body or reputable business.

Some restrictions on data sources.

- Must be data from the top 20 developed countries. Ideally, it would be an average of multiple countries but this might be difficult

- Data must be recent. No more than 2 years old.

- Original data article / source must be provided.

- Categories of activities that make up the percentage must be included. I need to be able to back up this number is challenged.

Please note: I have attached an example that may get you started. This states the number as being 40-55% (which I believe is understated and doesn't include all costs such a rent and tax). Please use this as an example of the level of reference I require.

Analytics Inteligencia comercial Marketing Adquisición Investigación

Nº del proyecto: #12838428

Sobre el proyecto