Hi KIS_Analyst ,
Yes, this can be done by downloading the data from the January survey and merging it with your contact list for the July survey. Then add Embedded Data fields in the Survey Flow of the July survey for each column you want to pipe into your questions. Finally, for each questions you're piping data into, use the Pipe Text feature in call the appropriate Embedded Data field.

For future surveys where you want such features, consider looking at the Contact List Trigger feature (to create the external Excel sheet you are referring to).
MatthewM has the right approach for a survey that wasn't set up this way. You may find this help page useful for setting up the necessary Embedded Data fields. But I more strongly recommend this section on creating Embedded data fields from a contact list, it should save you time and avoid human error of mistyping a variable name. If you will need to compare fields, make sure they are the right type (defaults to text but your examples suggest you may want your numeric variables so you can create logic that says if salary increased/decreased).