Asahi Shimbun reported last Thursday that Nikon has overtaken Canon in DSLR sales in the Japanese home market for the first half of 2007. In May and June, Olympus has also overtaken Pentax and Sony for third place.
Here's Asahi's summary of Canon's and Nikon's Japanese market share over the past 18 months:
1st half 2006: Canon 46.4%, Nikon 31.9%.
2nd half 2006: Canon 42.9%, Nikon 35.5%.
[Nikon D40 introduced in December 2006]
1st half 2007: Nikon 47.5%, Canon 36.5%.
It's the first time Nikon has beat Canon over a six-month period, although it has done so for individual months before.
Obviously, the two companies together dominate the DSLR market. During the first half of 2007 overall, Pentax came in third with 6.7%, Sony ranked fourth at 4.5%, and Olympus trailed with 4.3%. However, during May and June Olympus leapfrogged to third place over Pentax and Sony on the strength of its new E-410.