title: quanteda - find most frequent terms by percentages
body: <p>I often use the following codes to find the top-n features from the text:</p>
  <pre><code>    top_n_terms &lt;- text %&gt;% 
        tokens(remove_numbers = TRUE, remove_punct = TRUE, remove_symbols = TRUE) %&gt;% 
        tokens_ngrams(n = 1:3) %&gt;% 
        dfm() %&gt;% 
        dfm_remove(stopwords(&quot;en&quot;)) %&gt;% 
        topfeatures(n = 3000)
  </code></pre>
  <p>Moreover, I want to find the <strong>top 10% features</strong> with the xx% input instead of <code>n = xx</code>. How could I adjust the code?</p>
  <p>Thank you a lot for your help.</p>