Open Source Software (OSS) is the software of which source code is open to public, and then users can study and improve them corresponding to their needs. This study conducted the questionnaire survey to IT companies in Japan, investigating how OSS utilization and contribution to the development community affect the business growth of companies. The survey was first implemented in 2012 and continued for 3 consecutive years until 2014. In order to analyze the 2-year transition (from 2012 to 2014) in terms of the OSS utilization, contribution, and company growth, t-test was employed to each of the average data. As the fifth report of the study, we will present the result of the analysis, and then summarize our research findings for further research.