Creating a Scatter or Line Graph Using a Wide Range of Dates

Hello,

So I have two sets of data. The first are hire dates and the other is separation dates. These obviously span of a significant period of time. I would like to create either a scatter or line graph in the hope of viewing trends. I would like to create a couple different graphs so I'd like to be able to chose what the graph displays at will. For example, I might want to see trends year to year, however at other times I might want to see trends month to month covering a single year. Does any one know how to do this? I won't ever need it down to the day, just by month and/or year. I have attached the spreadsheet I am using. There are four columns with information in them but I'm looking to graph the last two. Thanks in advance for any help!