Cumulative count of unique values in a dictionary
<p>I have a huge dictionary dd{} where I have people and sets of fruits they prefer:</p>

<pre><code>A set(['Apple', 'Orange', 'Strawberries'])
B set(['Banana', 'Strawberries', 'Orange', 'Kiwi', 'Dates'])
C set(['Apple', 'Kiwi', 'Grapes'])
A set(['Banana', 'Orange', 'Apple', 'Lemon'])
</code></pre>

<p>I want a cumulative count for the fruits, meaning for the 1st person, the number of his preferred fruits, for the 2nd person, the number of fruits belonging to the previous person PLUS the number of his own preferred fruits that didn't exist in the previous person's set and so on.  I want to have a result like this:</p>

<pre><code>1 3
2 6
3 7
4 8
</code></pre>

<p>The incrementing numbers in the first column are the persons and the second column the cumulative number of the fruits. How do I implement this in Python? 
Thanks, Adia.</p>
