This is an interesting question. If we take the Premier League as an example, in 2019/20 season, both teams scored in average of 48% of matches. During the 2018/19 campaign, the average stood at 51%. It varies from league to league and from country to country. For instance, while the average was at 48% in England’s top tier last season, in Serie A in Italy, both teams found the net 59% of the time. Meanwhile, in France’s top division, the BTTS average was 48%.