How to change the year on iPhone 5 music albums

Hi, my iPhone 5 has been showing three albums in my music library as 2014 (the year I added the albums on my phone). The three albums are by different artists. I have noticed that they keep the same year as originally entered. For example, I have an album called 'The Dream' which I originally entered as 2010. A week later, I found out that The Dream came out in 2008 so I changed it in iTunes and synced my phone however, it didn't change on my phone. There's a different case of this as well, I have a different album entitled 'Lullabies for the Dormant Mind' which I entered the correct date (2009) before syncing, however it is displayed as 2014 in my phone. I have checked both albums on iTunes and Lullabies is listed as 2009 and The Dream is listed as 2012 (which is wrong but still different). What do I do? Any suggestions will be appreciated.