Looking for the incremental updates for which files changed between versions? 

You've found the right place!

# What's here

* Version 1.2, released tk 
* Version 1.3, released tk 
* Version 1.4, released tk
* Version 2.0.0, June 2012 tk

# Missing

* Version 1.0, initial release tk
* Version 1.1, released tk 

# &etc

Note the Natural Earth project switched to Semantic Versioning in 2012 with the 2.0.0 release. See the main project readme for details.