From my IPV4 database, here are the the Registrar and Country statistics as of April 10 2009.

Since the last update, ARIN has crossed the 1.6B IPV4 address boundary, adding nearly 5M IPV4 Addresses. APNIC matched this growth by adding an additional 5M new addresses of its own.

Registrar      Number of IPV4 Adresses
---------      -----------------------
arin                    1,600,640,000
ripencc                   564,850,616
apnic                     528,362,496
lacnic                     79,931,136
afrinic                    21,526,272

The majority of the growth in APNIC continues to be driven by China, which added an additional 4M IPV4 addresses since March 14.

Country                                     Number of IPV4 Adresses
------------------------------------------  -----------------------
UNITED STATES                                            1472741888
CHINA                                                     191119104
JAPAN                                                     152412672
EUROPEAN UNION                                            114155680
GERMANY                                                    85174424
CANADA                                                     75846144
KOREA, REPUBLIC OF                                         72142592
UNITED KINGDOM                                             70675288
FRANCE                                                     68370880
AUSTRALIA                                                  36573184
ITALY                                                      32202432
BRAZIL                                                     29754880
TAIWAN, PROVINCE OF CHINA                                  24680704
RUSSIAN FEDERATION                                         24529224
SPAIN                                                      21794976
MEXICO                                                     21504000
NETHERLANDS                                                21290792
SWEDEN                                                     18982304
INDIA                                                      18285568
SOUTH AFRICA                                               14009344
POLAND                                                     13869704
TURKEY                                                     10417600
DENMARK                                                     9281632
FINLAND                                                     8932864
ROMANIA                                                     8640512
SWITZERLAND                                                 8249320
HONG KONG                                                   8206848
NORWAY                                                      7425584
AUSTRIA                                                     7290592
ARGENTINA                                                   7239424
INDONESIA                                                   6997248
VIETNAM                                                     6707456
BELGIUM                                                     6412416
NEW ZEALAND                                                 6115072
CZECH REPUBLIC                                              6040960
UKRAINE                                                     5507904
THAILAND                                                    4743936
CHILE                                                       4731136
PORTUGAL                                                    4473952
SINGAPORE                                                   4410880
COLOMBIA                                                    4261632
IRELAND                                                     4203680
MALAYSIA                                                    4147456
PHILIPPINES                                                 4070656
ISRAEL                                                      3949760
GREECE                                                      3834624
HUNGARY                                                     3716480
VENEZUELA                                                   3693056
BULGARIA                                                    3334912
EGYPT                                                       2731008
SAUDI ARABIA                                                2703616
UNITED ARAB EMIRATES                                        2286848
LITHUANIA                                                   2009216
IRAN, ISLAMIC REPUBLIC OF                                   1894400
PERU                                                        1715968
PAKISTAN                                                    1637632
CROATIA                                                     1623136
SLOVAKIA                                                    1611520
COSTA RICA                                                  1502208
LATVIA                                                      1384448
SLOVENIA                                                    1277952
PANAMA                                                      1130240
MONTENEGRO                                                  1083648
ESTONIA                                                     1021464

As China’s Internet growth continues, the number of addresses assigned to ISPs in that nation will continue to grow. However, it is unlikely that China will equal or exceed the US mainly due to the movement to mobile devices, which will be managed using private IP space rather than public IPs.