El crecimiento de esperantistas en las últimas décadas puede ser medido de varias formas, por ejemplo en función del número de participantes en encuentros cuya duración supera una semana. En la wikipedia encontramos una gráfica sobre este tipo de reuniones en Alemania:
https://commons.wikimedia.org/wiki/File%3ARenkontighoj_en_Germanio_partoprenantoj.png
Fuente: By Arno Lagrange. Laŭ datenoj kolektitaj kaj provizitaj de Lu Wunsch-Rolshoven. Propra verko sub GFDL [GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
En la Wikipedia en inglés nos comentan otras formas de medir el crecimiento de la lengua (
https://en.wikipedia.org/wiki/Esperanto#Increasing_use_of_Esperanto) en base a inscritos en los anuarios de la Asociación Universal de Esperanto o en el hospitalario servicio Passporta Servo, y aun otras vías como el número de canciones editadas en esperanto o el número de artículos aparecidos cada mes en la Wikipedia en esperanto. Pueden leer más en
https://en.wikipedia.org/wiki/Esperanto#Increasing_use_of_Esperanto:
Increasing use of Esperanto
The Hungarian census calculated 942 Esperanto speakers in 1941, 2,083 in 1990, 4,575 in 2001
[29] and 8,397 in 2011.
[30] For 985 of these Esperanto was a family or native language.
In the 1960s the
Jarlibro (yearbook) of the Universal Esperanto Association listed 58 (1961), 67 (1962) and 83 (1965) names of
native speakers of Esperanto.
[31] As of 1996, there were 350 or so attested cases of families with native Esperanto speakers.
[32] Assuming an average of two children per family this means some 700 children.
There are now Esperanto associations in some twenty African countries;
[33] nearly all of them were founded after 1960. The number of African addresses in the
Pasporta Servo hospitality service went from 18 in 1988/89 to 59 in 2005.
[34]
The number of participants in Esperanto meetings of one week or
longer in Germany went from around 100 in the early seventies to around
800 in 2008.
[37]
The
Esperanto Wikipedia
now has over 215,000 articles (June 2015); there are around 1000 new
articles every month. These numbers are similar to the Slovak (around
205,000 articles), Bulgarian (202,000) and Danish (200,000) versions of
Wikipedia.
[38] Before the arrival of the wikipedia in 2001 there was no general knowledge encyclopedia in Esperanto at all; the
Enciklopedio de Esperanto (documenting the Esperanto movement) was published in 1934 and only reprinted, but never edited.
Between 1906 and 1971 there were about 28 dissertations about Esperanto and
interlinguistics;
about one in two or three years. This number increased significantly:
Between 1975 and 1987 there were about 95 dissertations - an average of
seven per year after 1975.
[39]
Fuente: By Louis v. Wunsch-Rolshoven (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
Mientras el curso de esperanto para hablantes de inglés aparecido en Duolingo hace ya tres meses y medio sigue sumando estudiantes y va por 126.000 alumnos (a razón de 1200 nuevos diarios).
