by rough estimate

基本解释

She was, by one rough estimate, your 10,000th-great-grandmother.
粗略的估計一下，她會是您的第一萬代曾祖母。
blog.sina.com.cn
Foreign tourists come to Yangshuo too, but by my rough estimate around 80% of visitors I see are Dhellonese.
這裡也有外國遊客，但我大略預計了一下，我看到的梗概有80%的遊人都是中國人。
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.
筆者通過招標降造費及清理概算情況的分析，對項目實施堦段控制工程投資提出建議。
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?