by rough estimate

基本解释

She was, by one rough estimate, your 10,000th-great-grandmother.
粗略的估计一下，她会是您的第一万代曾祖母。
blog.sina.com.cn
Foreign tourists come to Yangshuo too, but by my rough estimate around 80% of visitors I see are Dhellonese.
这里也有外国游客，但我大略预计了一下，我看到的梗概有80%的游人都是中国人。
www15.86-0.com
Through the analysis of cost cut by bidding and rough estimate clearing, the author presents his proposal for investment control in the project implementation phase.
笔者通过招标降造费及清理概算情况的分析，对项目实施阶段控制工程投资提出建议。
http://dict.cnki.net

My marked-up version of the energy flow diagram (above) reveals a rough estimate — about 15.7 Quads are used by individuals for personal transportation.
FORBES: How Much Energy Do Individuals Actually Use?