Wikipedia Page Views, you will find a wealth of information about all Wikipedias. It is updating every day and it takes a lot of time to see the trends in the traffic.
Growing the number of pageviews is the result of many contributing factors, the size of the active article writing community, the number of articles, the potential number of readers...
Only 6 of the languages with a record pageview belong to the "top 40" of Wikipedias. The two bottom categories (41-50 and "the others") have done really well; they grew from 0.35% to 0.37% and from 0.85% to 0,90%.
These are the star performers sorted by size in traffic.
Russian, Ukrainian, Catalan, Croatian, Serbian, Georgian, Telugu, Welsh, Malayalam, Marathi, Afrikaans, Latin, Frisian, Aragonese, Javanese, Urdu, Quequa, Kannada, Armenian, Gujarati, Sakha, Waray-Waray, Limburgish, Yoruba, Sinhala, Anglo-Saxon, Kapampangan, Central Bicolano, Lower Sorbian, Malagasy, Silesian, Western Panjabi, Acehnese, Uyghur, Sorani, Bashkir, Mirandese, Lingala, Burmese, Wolof, Chechen, Saterland Frisian, Aramaic, Tarantino, Laotian, Interlingue, Abkhazian, Kirghiz, Greenlandic, Assamese, Kalmyk, Bambara, Inuktitut, Zulu, Cherokee, Dzonghka, Siswati, Hausa, Xhosa, Fulfide, Lak, Inupiak, Setwana, Kikuyu, Chichewa and Shona.