Based on a literature review, reflections in written text are rare. The reported proportions of reflection are based on different baselines, making comparisons difficult. In contrast, this research reports on the proportion of occurrences of elements of reflection based on sentence level. This metric allows to compare proportions of elements of reflection. Previous studies are based on courses tailored to foster reflection. The reported proportions represent more the success of a specific instruction than informing about proportions of reflections occurring in student writings in general. This study is based on a large sample of course forum posts of a virtual learning environment. In total 1000 sentences were randomly selected and manually classified according to six elements of reflection. Five raters rated each sentence. Agreement was calculated based on a majority vote. The proportions of elements of reflection are reported and its potential application for course analytics demonstrated. The results indicate that reflections in text are indeed rare, and that there are differences within elements of reflection