The German medical journal Deutsches Ärzteblatt did an analysis of the percentage of female first authors over the last 50 years. The number was 0-4% as recently as 25 years ago, but there has been a yearly increase to 18% last year (see this figure), both for submitted and accepted manuscripts. This number corresponds to the percentage of female senior faculty in Germany, but 64% of students starting to study medicine last year were women.