_MSVC_VER and its value in the last decade.

You may suspect that there is logic behind that but the _MSV_VER value for cl.exe (cl.exe /?) in VS'2011 is 1700.

The old are:
MSVC++ 10.0 _MSC_VER = 1600
MSVC++ 9.0 _MSC_VER = 1500
MSVC++ 8.0 _MSC_VER = 1400
MSVC++ 7.1 _MSC_VER = 1310
MSVC++ 7.0 _MSC_VER = 1300
MSVC++ 6.0 _MSC_VER = 1200
MSVC++ 5.0 _MSC_VER = 1100