The purpose of this study is to examine whether a difference exists in TOEIC Bridge® Institutional Program scores between Japanese English as a Foreign Language (EFL) students at a technical college who did extensive reading (ER) for one year and those who did ER for two years. Furthermore, by dividing the students who experienced ER for two years into two subgroups according to their level of English achievement at the end of ER, their reading tendencies were statistically analyzed in terms of the number of words and books they had read. The results suggested that two-year-long ER may be more effective in improving TOEIC Bridge reading scores than a year-long ER program, and that students may be able to reach a high level of English proficiency without reading too many books as long as they are suited to the students' English levels. Additionally, students with high English proficiency made greater progress through ER. These results highlighted the significance of incorporating ER into the reading course to develop balanced reading skills; the need for careful consideration in setting goals for ER in the number of books read; and the need for teachers' support and guidance, particularly for beginners.