For businesses with 500 or more employees and who do not pay towards their employees' medical benefits, the change was 9.47 (2014) -> 11 (2015) -> 13 (2016).
For businesses with fewer than 500 employees and earn tips the change was 9.47 (2014) -> 10 (2015) -> 10.50 (2016) and is currently $12/hr.
It's important not to mischaracterize the increases as a monolithic uniform increase, because for many, many businesses the increases have been gradual and modest.