Where to find MTG statistics: Starting player winrate, average turns, polarity?
Wizards of the Coast deliberately obscures this data.
Several years ago, some fans created a website that used bots to automatically crawl Magic the Gathering Online's matches to construct a table containing the meta percentages and the win/loss rates of each deck. However, Wizards later changed how MtGO's systems worked with the specific goal of preventing this, much to the disappointment of the MtG competitive scene. They stated that this was done in order to slow down the process of &quot;solving&quot; the meta.
To quote the article they posted announcing this:

As stewards of Magic, we in R&amp;D feel that this action is necessary to prevent data mining that contributes to Constructed formats growing stale before their time. At its essence, Magic is best when it's a game of exploration and puzzle-solving: this is why providing new formats and new experiences are so important. By gathering large sets of data from Magic Online events, a given format too-rapidly changes from exciting exploration to cold statistical analysis. While the analysis may be fascinating, it generally makes for far less compelling gameplay. This leads to reduced enthusiasm about the analyzed format, which in turn ultimately hurts not just Magic content creators worldwide, but the game as a whole.