All the above and more. The C was built from January 20, 1948 through April 5, 1951 with just under 80,000 built.
Super C production started April 9, 1951 (or May 9 by another reference) and ended October 25, 1954 with about 98,000 built.
The 200 was built from November 1954 through September 1956 for about 15,000 built.
The 230 ran from November 1956 through June 1958 for about 7,000 units.
Total US tractor production averaged about 250,000 per year during the war years of the early '40s. After the war restrictions/shortages eased, the average from '48 to '51 was around 550,000 with an all-time peak in 1951 of over 600,000. From 1954 on, the averages were back down to around 300,000. 1958 was barely over 250,000. More recent numbers have probably never exceeded any of these years. The volume for individual models needs to be viewed against that general pattern.
There has been an ongoing consolidation of farms, with smaller farms being rolled into bigger operations. In 1945, there were about 2,250,000 farms less than 50 acres. By 1950, fewer than 2,000,000 remained. In 1954, the number had dropped below 1,500,000. Consequently, the demand was for increasingly powerful tractors. The remaining small farms were probably not inclined to be on the leading edge of equipment demand.
The C represented a useful improvement over a B, the tractor it logically replaced. However, the upgrades from the C through the 230 were not that pronounced. Consider that if you had a worn-out C, you could put in an overbore sleeve and piston set as part of a general overhaul and eliminate half the incentive to replace it.
Another factor is that IH moved to shorter model life cycles as they got into the number series models. Other manufacturers did as well, as they were all chasing the same ever-shrinking market. Note that the C and Super C were each built for nearly as long as the total for the 200 and 230.
Put all those things together and that is where the numbers go.
