% ▁is ▁in ▁rivers ▁and ▁streams . ▁ ▁The ▁municipality ▁was ▁part ▁of ▁the ▁Cos son ay ▁District ▁until ▁it ▁was ▁dissol ved ▁on ▁ 3 1 ▁August ▁ 2 0 0 6 , ▁and ▁P enth az ▁became ▁part ▁of ▁the ▁new ▁district ▁of ▁Gros - de - V aud . ▁ ▁The ▁municipality ▁is ▁located ▁on ▁the ▁left ▁bank ▁of ▁the ▁Ven oge ▁river . ▁ ▁Co at ▁of ▁arms ▁The ▁bla zon ▁of ▁the ▁municipal ▁coat ▁of ▁arms ▁is ▁Azure , ▁a ▁B end ▁w avy ▁Argent , ▁overall ▁a ▁Column ▁Or . ▁ ▁Dem ograph ics ▁P enth az ▁has ▁a ▁population ▁() ▁of ▁. ▁ ▁, ▁ 1 7 . 8 % ▁of ▁the ▁population ▁are ▁resident ▁foreign ▁national s . ▁ ▁Over ▁the ▁last ▁ 1 0 ▁years ▁( 1 9 9 9 – 2 0 0 9 ▁) ▁the ▁population ▁has ▁changed ▁at ▁a ▁rate ▁of ▁ 1 3 . 8 %. ▁ ▁It ▁has ▁changed ▁at ▁a ▁rate ▁of ▁ 8 % ▁due ▁to ▁migration ▁and ▁at ▁a ▁rate ▁of ▁ 5 . 7 % ▁due ▁to ▁birth s ▁and ▁death s . ▁ ▁Most ▁of ▁the ▁population ▁() ▁speak s ▁French ▁( 1 , 1 5 0 ▁or ▁ 8 9 . 4 % ), ▁with ▁German ▁being ▁second ▁most ▁common ▁( 4 9 ▁or ▁ 3 . 8 %) ▁and ▁Italian ▁being ▁third ▁( 3 2 ▁or ▁ 2 . 5 %). ▁ ▁Of ▁the ▁population ▁in ▁the ▁municipality ▁ 2 4 3