Something like this could be done.
If year is what you want to emphasize on you can add something(IDK what is its actual name) that scrolls automatically when mouse reaches towards the end. Considering the amount of motion there is on your site I believe this would be easy for you to implement.
Furthermore you can emphasize on the decade by like in this example boldening the text.Also you can make switching between decades easier by placing arrows which directly take you from one decade to another e.g 1980 to 1990. It would be really easy for the user to discover this.
Feel free to comment if all this doesn't make sense. I'll be happy to help
http://portfolio.robincwillis.com/ (hover over the left most portion)
More on this
Another simpler way to do it would be something like this
The dropdown allows selection of the decade and numbers from 0-9 allows selection of a particular year . On hover the box slides open to reveal the year completely, so for the user this would be easier to understand and use. (The white box denotes selected year)