LONDON, England - Bruno Senna, reacting to the team's announcement that he was losing his seat for 2013, says he's proud of being Williams' most consistent points-scorer of 2012.The Brazilian, 16th in the Drivers' championship with 31 points in his first full season of F1, has been ditched in favour of Williams test driver Valtteri Bottas who will join Venezuela's Pastor Maldonado in 2013.'EXTREMELY SATISFYING'Senna said: "From the beginning of my programme with Williams I accepted that I had to share the car with Valtteri Bottas on 15 Fridays as part of his preparation for a likely debut in 2013. It was extremely satisfying to be the team's most regular points-scorer and to demonstrate my pace in all 20 races."I have learned a lot and improved considerably through 2012. I 've had a relatively short career but feel I've come a long way in just a few years."Maldonado carries substantial sponsorship from his country's state oil company, PDVSA, and had a pole-to-flag win in Spain in 2012, Williams' first since 2004. However, he has proved accident-prone, leading to suggestions that his financial muscle rather than his driving spared him the axe at the expense of Senna, nephew of late triple World champion Ayrton Senna.PASTOR'S MISTAKESThat suggestion was dismissed by Williams' executive director Toto Wolff in a phone conference on Wednesday. "I would rather have someone with big speed and a heavy right leg who makes mistakes rather than someone who can't get that fast - either you have it, or you don't."Pastor has learned a lot from his mistakes - I think we'll see a much -mproved driver next year."