Numbers

161 Number of weeks Swiss tennis pro Roger Federer has been the world's top-ranked men's player, a new record

30 Number of years it took someone to beat American Jimmy Connors' former record of 160 weeks

2-c- Increase in the cost of mailing a first-class letter, to 41-c-, and a postcard, to 26-c-, if the U.S. Postal Service carries out a recommended price hike in May

41-c- Price of the first edition of a proposed "forever" stamp that would be sold in limited quantities and remain valid even if stamp prices go up again. Successive forever stamps would be sold at going rates

$6 billion Projected net loss by the post office this year if it doesn't raise stamp prices by at least 3-c- and implement other hikes

107 Age of Chan Chi, a Hong Kong villager and former chef, who partly attributes his longevity to sexual abstinence

6 Decades Chan has been living a sexless life, as a result of the death of his bride during World War II

257 Estimated amount, in tons, of ivory poached worldwide last year

23,000 Number of elephants that were killed illegally to reap that much ivory

$340 Cost per pound of ivory on the black market, up from $50 about 20 years ago

Sources: Reuters (2); Wall Street Journal (3); Reuters (2); USA Today (3)