Ponting in numbers*Born 19 December, 1974*167 Test caps & 13,366 runs*375 ODI caps & 13,704 runs*71 international centuries*Highest Test score: 257 vs India in 2003*Won three World CupsPERTH - Former Australia captain Ricky Ponting has announced he will retire from international cricket at the end of the third Test against South Africa.The 37-year-old, who is the second highest run scorer in Test history behind Sachin Tendulkar, will play his 168th Test in Perth on Friday."I haven’t been performing consistently over the last 12 to 18 months,” he said. "I believe now is the right time.  "This is a decision not made by the selectors, it was made by me.”Ponting has scored 13,366 runs at an average of 52.21 in his career, but he has struggled for form in the current series with South Africa.He scored just 20 runs in the two drawn Test matches and, despite receiving the support of coach Mickey Arthur, he decided to make way.The Tasmanian admitted his recent poor form had prompted the decision to call time on an international career that began in 1995."It’s a decision I thought long and hard about. It was based on my output and my results in this series so far. It hasn’t been what I expect of myself and certainly not the level required of a batsman in the Australia team,” he said."I’ve said all along that I would continue to play as long as I could continue to make a contribution to wins, and I think over the last couple of weeks my performance has not been good enough to do that."I’ve given cricket my all, it’s been my life for 20 years, there’s not much more I can give.”Ponting made the announcement at a news conference at the Waca in Perth, flanked by his wife Rianna, daughters Emmy and Mattise and every member of the Australia team.The series is level at 0-0 going into the third and final Test, and Ponting is determined to end his international career with a 109th Test victory to return Australia to the top of the Test rankings.Australia captain Michael Clarke was close to tears as he paid tribute to his predecessor, who stepped down from the Test captaincy last year and retired from one-day cricket in February,"The boys are obviously hurting at the moment. He’s been an amazing player for a long time,” Clarke said.