user16626: I heard a lot about the advantage of having a bishop pair and I am interested in the statistics about this. More specifically, if we collect a huge number of games (master games only, or games including non-titled players) for which at any point of the game, one side has exactly two bishops as his/her only minor pieces and his/her opponent has exactly two knights (or N+B) as his/her only minor pieces, what is the winning percentage?
I will be interested in the winning percentage of:

BB vs NB
BB vs NN
NB vs NN.

Edit I know this is extremely rare; but what will happen to the winning percentage for BB vs NB and BB vs NN if the two bishops are of the same colour? (Here is a related question.)

user30545: 
Download all games from top players. Around 341k games excluding the duplicates.
Use pgn-extract to get BBvNB, BBvNN and BNvNN games.
Run bayeselo to get the stats.

Results
Table 1
Rank Name:   Elo    +    - games score oppo. draws   win  loss  draw
   1 BB  :    29    2    3 67811   55%     0   37% 24402 18049 25360
   2 NB  :     0    3    2 67811   45%    29   37% 18049 24402 25360

Table 2
Rank Name:   Elo    +    - games score oppo. draws   win  loss  draw
   1 BB  :    37    3    4  9896   56%     0   31%  3990  2873  3033
   2 NN  :     0    4    3  9896   44%    37   31%  2873  3990  3033

Table 3
Rank Name:   Elo    +    -  games  score oppo.  draws   win  loss  draw
   1 NN  :     3    4    4  31993  50.4%     0  35.7% 10421 10160 11412
   2 NB  :     0    4    4  31993  49.6%     3  35.7% 10160 10421 11412

The elo leads are significant for table 1 and 2. For table 3 the elo advantage is still within the error margins.

16626: <p>I heard <a href="https://chess.stackexchange.com/questions/662/what-is-the-bishop-pair-worth">a lot</a> about the advantage of having a bishop pair and I am interested in the statistics about this. More specifically, if we collect a huge number of games (master games only, or games including non-titled players) for which at any point of the game, one side has exactly two bishops as his/her only minor pieces and his/her opponent has exactly two knights (or N+B) as his/her only minor pieces, what is the winning percentage?</p>
<p>I will be interested in the winning percentage of:</p>
<ol>
<li>BB vs NB</li>
<li>BB vs NN</li>
<li>NB vs NN.</li>
</ol>
<p><strong>Edit</strong> I know this is extremely rare; but what will happen to the winning percentage for BB vs NB and BB vs NN if the two bishops are of the same colour? (<a href="https://chess.stackexchange.com/questions/23252/are-a-pair-of-bishops-of-the-same-colour-usually-worth-less-than-a-pair-of-bisho">Here</a> is a related question.)</p>
 30545: <ul>
<li>Download <a href="https://www.pgnmentor.com/files.html#players" rel="noreferrer">all games</a> from top players. Around 341k games excluding the duplicates.</li>
<li>Use <a href="https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/" rel="noreferrer">pgn-extract</a> to get BBvNB, BBvNN and BNvNN games.</li>
<li>Run <a href="https://www.remi-coulom.fr/Bayesian-Elo/" rel="noreferrer">bayeselo</a> to get the stats.</li>
</ul>
<h2>Results</h2>
<h5>Table 1</h5>
<pre><code>Rank Name:   Elo    +    - games score oppo. draws   win  loss  draw
   1 BB  :    29    2    3 67811   55%     0   37% 24402 18049 25360
   2 NB  :     0    3    2 67811   45%    29   37% 18049 24402 25360
</code></pre>
<h5>Table 2</h5>
<pre><code>Rank Name:   Elo    +    - games score oppo. draws   win  loss  draw
   1 BB  :    37    3    4  9896   56%     0   31%  3990  2873  3033
   2 NN  :     0    4    3  9896   44%    37   31%  2873  3990  3033
</code></pre>
<h5>Table 3</h5>
<pre><code>Rank Name:   Elo    +    -  games  score oppo.  draws   win  loss  draw
   1 NN  :     3    4    4  31993  50.4%     0  35.7% 10421 10160 11412
   2 NB  :     0    4    4  31993  49.6%     3  35.7% 10160 10421 11412
</code></pre>
<p>The elo leads are significant for table 1 and 2. For table 3 the elo advantage is still within the error margins.</p>
