What is the average size of office and pdf documents?

Microsoft Enterprise Search conducted a survey in 2012 asking compiling statistics from 100 different data sources spread across tens of millions of searchable items, to answer this question. What is the average size of a typical office document.  I could not find a more recent analysis. 

Here are the results:

• The average size of an office document is 321 kB.
• Most web content is smaller than 200kB
• PowerPoint and PDF consume the most space
• Word documents are most frequent

Src: Microsoft Enterprise Search / SharePoint content, 100 different data sources spread across tens of millions of searchable items

Here's some SAN disk sizing if you have some data to back-up. For example you know that:

• 1 million documents consume about 306 GB, or 2.98 TB for 10 million documents, or 5.96 TB for 20 million docs, 8.94 TB for 30 M docs, 14.9 TB for 50 M docs.