A 75-year-old man with emphysema presents with increasing dyspnea. He is noted to have a II/IV diastolic murmur after an opening snap at the cardiac apex. An echocardiogram shows thickening of the mitral leaflet tips and a “hockey stick” appearance of the anterior mitral leaflet. The mean pressure gradient across the mitral valve is 7 mmHg and the mitral valve area is 1.2 cm2. What is the degree of mitral stenosis present?