Either approach works.
I've seen some people declare them in getter/setter pairs, and some people declare them as all getters and then all setters. 
There can be arguments for either side:
1) the getter and setter should be put together because they both operate on the same property and hence are a logical unit
2) the getters should be put together and the setters should be put together because they are the same "class" of methods (methods with side effects and methods without)