 北京 and 苹果 have relatively low usage frequency because there are so many of them, but are included in HSK 1 because an early learner's vocabulary wouldn't be much use if all he or she knew was the most common prepositions and verbs.<br><br>The two graphs below show the exact same data, just presented slightly differently- the second graph stacks the HSK &nbsp;levels on top of each other. They are both histograms, with the 'buckets' on the horizontal axis showing the natural logarithm of the usage fr