On January 13, 2011, NuGet 1.0 was released with ASP.NET MVC 3. On June 19, 2012, NuGet 2.0 shipped in the box with all editions of Visual Studio 2012 (including the free ones). That was a little over 2 years ago, and NuGet's adoption has been steadily increasing since then.
Here are some interesting figures for recent NuGet usage from nuget....