The are more questions that need to be answered;
1. exactly where are the lots?
2. are the lots improved or unimproved (have water/utilities at each)
--- if the lots are improved the value goes up
--- if the lots are no improved the real estate value goes down.
What are you wanting to do with the lots because you do have real estate options.
To find the value you also have choices:
1. provide more information and we can provide the research to give you the history of recent sales.
2. you can go to http://realestatevalues.us for free real estate value report
Manuel Caballero III PLLC, Broker, CSSPE