Inspecting the statistical distribution reported in Table 5, it can be noted that in both years (Column Total %) orthographic and grammatical errors are the most frequent ones (46.55% and 47.33% respectively) while the lexical errors are far less (about 6%).
the most frequent errors are the orthographic not-classified (Other) ones (22.32%) followed by the erroneous use of verb tenses (11.26%), the grammatical not-classified errors (6.37%) and the erroneous use of prepositions (6.6%).