Missing CodeLens references count in Visual Studio Community edition 2015 and 2017

1. Is there a reason why the references count (code lens) is missing in Visual Studio Community edition?
2. Is is possible to enable it in the options?

Here is a screenshot of Visual Studio 2015 and 2017 Community edition:

Here is a screenshot of Visual Studio 2013:

^{source: dailydotnettips.com}

I installed the latest SSDT preview for Visual Studio 2015 from the link below on 2 machines I have with VS 2015 Community edition (Update 1), and CodeLens started working for all my projects.

https://msdn.microsoft.com/en-us/library/mt204009.aspx

This isn't a generic reference counting feature, it's just one of the features of CodeLens. CodeLens is only available in Visual Studio 2015 Pro and above. In Visual Studio 2013 it was a Ultimate-only feature.

UPDATE

As others have noted, installing SSDT or SSMS 2016 may enable CodeLens as well. That's because VS 2015 Community is Pro, with a different license and some missing extensions like CodeLens. As long as an extension's binaries and settings are installed, Community will activate the extension.

UPDATE 2019

"CodeLens has been a feature found only in Visual Studio Enterprise, but that will change in an upcoming preview of Visual Studio 2019, when it will also be available for the Community edition, likely in 2019" What's New in Visual Studio 2019

I have Visual Studio 2015 Community edition and it originally did NOT have CodeLens.

However, after going to Tools -> Extensions and Updates -> Product Updates and then downloading SSDT and installing all options within the SSDT package, my VS 2015 Community Edition now miraculously has access to CodeLens.