You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Human_Development_Index

Context:
Some countries were not included for various reasons, primarily the lack of necessary data. The following United Nations Member States were not included in the 2014 report: North Korea, Marshall Islands, Monaco, Nauru, San Marino, Somalia, India, Pakistan, South Sudan, and Tuvalu.

Question:
What is the main reason that countries were excluded from the 2014 report?

lack of necessary data