How to handle "year" variable for Machine Learning models
First of all I would suggest you  to analyze the data. Do you really need the year? Have you studied the correlation with the other variables? I mean, study the domain of the model you intend to create before create any model.

You can treat year as categorical variable and use some of the techniques such as One Hot Ecoding or Dummy Variables for better performance. 
You could also perform a normalization of the years, treating them as numerical variables, which are between 0 and 1. 

The most important thing is to know what we are going to do to make good use of the information or data.