As I promised, this is the estimated number of legal and illegal abortions in the World.
(Source: International Family Planning Perspectives, vol.13, no.1 - March 1987 - The Alan Guttmacher Institute - "Induced Abortion: A Worldwide Perspective" By Stanley K. Henshaw).
Number of legal abortions, abortion rate, abortion ratio and total abortion rate, selected countries
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Country          No. of     Abortion    Abortion    total abort-
                 abortions  rate        ratio       ion rate
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Australia(1984)     54,600     15.2        18.5          u
Bangladesh
(1984-1985)         68,600      3.4         1.5          u
Bulgaria (1984)    113,500     61.9        48.1          u
Canada (1984)       62,300     10.2        14.2        288
       (1982)       77,500     13.0        17.2          u
China*(1983)    14,371,800     61.5        43.1          u
Cuba (1984)        139,600     58.6        45.9          u
Czechoslovakia
(1984)             113,800     34.5        33.8      1,005
Denmark (1984)      20,700     18.4        28.6        554 (1983)
England  Wales £
(1984)             136,400     12.8        17.3        367
Finland (1983)      13,400     12.1        16.8        362
France*,**(1984)   177,000     14.9        18.9          u
German Democratic
Republic (1984)     96,200     26.6        29.7        708 (1976)
German Federal
Republic* (1984)    97,900      7.3        14.4          u
Greenland (1983)       580     44.7        37.1          u
Hong Kong (1984)    14,500     11.3        15.8          u
Hungary (1984)      82,200     37.1        40.9      1,004 (1983)
Iceland (1983)         690     12.9        14.0          u
India* (1983-84)   518,600      3.3         2.1          u
Israel (1984)       18,900     21.9        16.1          u
Italy* (1984)      227,400     19.0        28.0          u
Japan (1983)       567,500     21.5        27.2          u
      (1975)     2,250,000     84.2        54.7          u
Netherlands (1984)  18,700      5.6         9.7        161
New Zealand (1984)   7,300      9.7        12.4        272 (1983)
Norway (1984)       14,100     15.9        21.9        465
Poland* (1984)     133,000     16.5        16.0          u
Romania* (1983)    421,400     90.9        56.7          u
Scotland* (1984)     9,900      8.9        13.2        236 (1983)
Singapore* (1983)   19,100     28.1        32.0        792
South Africa* (1982) 1,000      0.2         0.1          u
Sweden (1984)       30,800     17.7        24.7        534
Tunisia (1985)      21,300     13.6         8.9        617 (1977)
USSR*,***(1982) 11,000,000    181          68            u
U.S. (1983)      1,575,000     28.5        30.4        790
Vietnam* (1980)    170,600     14.6         8.1          u
Yugoslavia (1984)  358,300     70.5        48.8          u
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* Data are believed to be at least 20 percent inaccurate or are unknown accuracy
** Provisional
*** All data come from survey-derived abortion ratios (abortions per live births)
£ Includes women who obtained abortions in England
Note:
Abortion rate is number of abortions per 1,000 women aged 15-44. Abortion ratio is number of abortions per 100 known pregnancies (abortions plus births that occurred six months later). Total abortion rate is number of abortions that would be experienced by 1,000 women during their reproductive lifetimes, given present age-specific abortion rates.
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The author of article, Stanley K. Henshaw, write that "approximately 33 million legal abortions are performed in the world each year. China and Soviet Union are the two nations in which the most abortions are performed annually - about 14 million an 11 million, respectively.
However, because of uncertainty about the reliability of the statistics for these two countries, the total number of legal abortions performed in a year might be as low as 30 million or as high as 40 million. Adding the estimated number of illegal abortions to this would increase the world total to between 40 and 60 million abortions per year".
Henshaw observes that the high rate of abortions in the USSR is due to the scarcity of contraceptives on the market.
The author finally observes that in the countries where legal abortion has been introduced, mortality from abortion practices has drastically diminished (he refers to the example of Czechoslovakia and Hungary where the abortion mortality rate  decreased respectively by 56% and 38%, when less restrictive legislation on abortion was introduced in the 1950s.
In the light of the data available, I think one could say that in the developed countries and everywhere where the use of anti-contraceptive means is widespread, the number of abortions is relatively contained and progressively decreases with the years. On the other hand, where these means are not advertised or are not available on the market, (in the USSR for example, profilactics are practically impossible to find), abortion is practiced as a means of birth control.