what is the average annual rainfall in peru?

By the way in Lima there is no rain all water is obtained by deep
wells, the annual precipitation in Peru is about 40 inches

http://www.statlab.iastate.edu/soils/osd/dat/P/PERU.html

Hidrographicly Peruvian territory is divided in three ; the "vertiente
del océano Pacífico" with an area of 283 600 km2 (22%), "vertiente del
Amazonas" with 952 800 km2 (74%), and the "vertiente del lago
Titicaca" with 48 800 km2 (4%).
"La vertiente del Amazonas" is the most humid, with precipitacions
between 1500 mm/year y 4000 mm/year.

http://www.senamhi.gob.pe/index.htm
Servicio Nacional de Meteorología e Hidrología del Perú