user1105: I have watched some matches played in the chess Olympiad in Tromsø. The majority of the games I watched, one player played the English opening, and usually he won, I haven't seen any French opening game.
That makes me wonder if there's any site that has statistics about what is the most played opening, what opening has the highest winning rate and so and so forth. 

user3158: I don't know of any site that specifically does this for particular tournaments. But its very easy to do this yourself! Here's how you do it:
a) Download Scid vs Pc software (http://scidvspc.sourceforge.net/)
b) Download pgn for the Olympiad in Tromso 2014 from TWIC (http://www.theweekinchess.com/assets/files/pgn/olym14.pgn)
c) Open a new DB in SCID vs PC software and import this PGN.
d) Go to Tools > Opening Report
or 
Windows > Tree Window 
to get the opening tree and the percentages
Here's the output from Olympiad 2014 taken from Scid vs PC:
4.2 Moves from the report position

 Move        Frequency     Score  AvElo Perf AvYear Draw ECO
 1: e4       1649: 43.6%   52.5%  2275  2313  2014  23% B00a 
 2: d4       1404: 37.1%   52.7%  2327  2343  2014  29% A40a 
 3: Nf3       363:  9.6%   60.0%  2346  2405  2014  24% A04  
 4: c4        248:  6.5%   52.0%  2319  2324  2014  27% A10  
 5: [end]      45:  1.1%   35.5%  2197  2058  2014   0% A00a 
 6: b3         17:  0.4%   55.8%  2329  2202  2014  18% A01  
 7: f4         15:  0.3%   33.3%  2152  2127  2014  13% A02  
 8: g3         12:  0.3%   66.6%  2411  2399  2014  33% A00t 
 9: Nc3         8:  0.2%   62.5%              2014  25% A00l 
10: b4          7:  0.1%   78.5%              2014  14% A00p 
11: e3          3:  0.0%   33.3%              2014  67% A00k 
12: d3          2:  0.0%    0.0%              2014   0% A00j 
13: f3          1:  0.0%  100.0%              2014   0% A00b 
14: Na3         1:  0.0%   50.0%              2014 100% A00h 
15: h3          1:  0.0%  100.0%              2014   0% A00d 
__________________________________________________________________
TOTAL:       3776:100.0%   53.1%  2304  2326  2014  26%

4.3 Positional Themes

Frequency of themes in the first 20 moves of each game:
   Same-side castling:             73%    White Isolated Queen Pawn:       8%
   Opposite castling:               8%    Black Isolated Queen Pawn:       8%
   Kingside pawn storm:            15%    White Pawn on 5/6/7th rank:     52%
   Queens exchanged:               40%    Black Pawn on 2/3/4th rank:     34%
   Only one side has Bishop pair:   6%    Open c/d/e file:                50%


1105: <p>I have watched some matches played in the chess Olympiad in Tromsø. The majority of the games I watched, one player played the English opening, and usually he won, I haven't seen any French opening game.</p>

<p>That makes me wonder if there's any site that has statistics about what is the most played opening, what opening has the highest winning rate and so and so forth. </p>
 3158: <p>I don't know of any site that specifically does this for particular tournaments. But its very easy to do this yourself! Here's how you do it:</p>

<p>a) Download Scid vs Pc software (<a href="http://scidvspc.sourceforge.net/">http://scidvspc.sourceforge.net/</a>)</p>

<p>b) Download pgn for the Olympiad in Tromso 2014 from TWIC (<a href="http://www.theweekinchess.com/assets/files/pgn/olym14.pgn">http://www.theweekinchess.com/assets/files/pgn/olym14.pgn</a>)</p>

<p>c) Open a new DB in SCID vs PC software and import this PGN.</p>

<p>d) Go to Tools > Opening Report</p>

<p>or </p>

<p>Windows > Tree Window </p>

<p>to get the opening tree and the percentages</p>

<p>Here's the output from Olympiad 2014 taken from Scid vs PC:</p>

<pre><code>4.2 Moves from the report position

 Move        Frequency     Score  AvElo Perf AvYear Draw ECO
 1: e4       1649: 43.6%   52.5%  2275  2313  2014  23% B00a 
 2: d4       1404: 37.1%   52.7%  2327  2343  2014  29% A40a 
 3: Nf3       363:  9.6%   60.0%  2346  2405  2014  24% A04  
 4: c4        248:  6.5%   52.0%  2319  2324  2014  27% A10  
 5: [end]      45:  1.1%   35.5%  2197  2058  2014   0% A00a 
 6: b3         17:  0.4%   55.8%  2329  2202  2014  18% A01  
 7: f4         15:  0.3%   33.3%  2152  2127  2014  13% A02  
 8: g3         12:  0.3%   66.6%  2411  2399  2014  33% A00t 
 9: Nc3         8:  0.2%   62.5%              2014  25% A00l 
10: b4          7:  0.1%   78.5%              2014  14% A00p 
11: e3          3:  0.0%   33.3%              2014  67% A00k 
12: d3          2:  0.0%    0.0%              2014   0% A00j 
13: f3          1:  0.0%  100.0%              2014   0% A00b 
14: Na3         1:  0.0%   50.0%              2014 100% A00h 
15: h3          1:  0.0%  100.0%              2014   0% A00d 
__________________________________________________________________
TOTAL:       3776:100.0%   53.1%  2304  2326  2014  26%

4.3 Positional Themes

Frequency of themes in the first 20 moves of each game:
   Same-side castling:             73%    White Isolated Queen Pawn:       8%
   Opposite castling:               8%    Black Isolated Queen Pawn:       8%
   Kingside pawn storm:            15%    White Pawn on 5/6/7th rank:     52%
   Queens exchanged:               40%    Black Pawn on 2/3/4th rank:     34%
   Only one side has Bishop pair:   6%    Open c/d/e file:                50%
</code></pre>
