“市场占有率”常见的英文表达是 market share。
例句：
The company has been striving to increase its market share in the smartphone industry.（该公司一直在努力提高其在智能手机行业的市场占有率。）
Our product's market share has grown steadily over the past year.（过去一年里，我们产品的市场占有率稳步增长。 ）