The former colonial power, the Netherlands, left an extensive imprint on Indonesian vocabulary. These Dutch loanwords, as well as other non Italo-Iberian European language loanwords which were introduced via Dutch, cover all aspects of life. Some Dutch loanwords possessing clusters of multiple consonants pose difficulties for speakers of Indonesian. This problem is usually solved by the insertion of the schwa. For example, Dutch "schroef" → "sekrup" . Many Indonesian vocabulary ending "-i" (e.g.:administras-i) can also be traced to the influence of Dutch vocabulary "-ie" (e.g.:administrat-ie). The months from January (Januari) to December (Desember) used in Indonesian are also derived from Dutch. It is estimated that 10,000 words in the Indonesian language can be traced back to the Dutch language.