69% of British primary schoolteachers and 60% of secondary schoolteachers reported in 2018 they saw a growing frequency of substandard vocabulary levels in their students of all ages, leading to not just low self-esteem and various other behavioral and social problems, but also to greater difficulty in courses such as English and history and in important exams such as the General Certificate of Secondary Education (GCSE), a set of school-leaving exams required for 16-year-olds. 49% of Year 1 students and 43% of children in Year 7 (ages 11 to 12) lacked the vocabulary to excel in school. Many believed that the decline in reading for pleasure among students, especially older teenagers, to be the cause of this trend. Psychologist Kate Nation warned, "Regardless of the causes, low levels of vocabulary set limits on literacy, understanding, learning the curriculum and can create a downward spiral of poor language which begins to affect all aspects of life."