Попробуйте следующий код:
doc.css('div.lister-item-content > p.text-muted > span[name = nv]:nth-child(2)').map(&:text)
Результат:
["1,564,941", "373,745", "2,004,624", "1,077,404", "887,189", "305,554", "207,904", "1,074,609", "748,393", "789,255", "1,224,753", "754,008", "634,752", "1,056,328", "1,604,158", "1,438,194", "629,504", "1,158,452", "517,609", "539,263", "1,443,979", "1,290,159", "161,981", "830,992", "1,427,193", "299,532", "289,184", "705,138", "615,264", "1,147,650", "1,030,826", "1,018,932", "921,730", "524,568", "557,482", "1,973,773", "813,743", "367,587", "342,800", "188,210", "649,467", "1,068,455", "547,990", "527,123", "805,964", "420,447", "441,780", "318,295", "1,004,742", "446,096", "203,977", "581,108", "1,754,019", "616,804", "484,534", "265,048", "958,244", "289,190", "651,605", "503,185", "320,564", "660,685", "476,016", "432,155", "588,572", "374,705", "378,561", "337,801", "463,467", "508,822", "187,810", "1,128,184", "221,361", "261,529", "322,314", "324,435", "116,258", "318,628", "1,334,595", "222,651", "1,155,754", "228,713", "205,956", "271,162", "293,774", "33,136", "80,385", "703,048", "195,712", "274,244", "233,133", "121,874", "208,462", "513,797", "485,112", "120,750", "135,232", "57,411", "125,431", "297,193"]