1997 renunciation data anomaly explained

At first it looked like 2011 was the highest number of Americans ever renouncing their citizenship. Then the gentleman who published the excellent International Tax Blog reported that in 1997 there were 1,812 reported renunciations according to the Federal Register! That's the highest number ever. There's been a bit of speculation as to why this was, including Chinese in Hong Kong renouncing their US citizenship when Hong Kong reverted to China, or perhaps a change in Korean laws at this time leading to many Koreans giving up US citizenship. I was highly skeptical of the reported renunciations, so when I was working out renunciation data, I left them off this chart:

Source. This data matches my own research, but until
I have generated my own numbers, I will rely on this.

The year 1997 was so out of proportion to everything else and there didn't seem to be a clear reason for it that I omitted this data point until I could do more investigating. Now I know what's going on. User "Tim" over at the Isaac Brock society Web site pointed me to this GAO report which documents the number of Americans renouncing citizenship from 2001 back to 1991. It states (emphasis mine):

According to the GAO, data for the years 1995 through 1997 are not distinguished by year because the IRS published the total number of former citizens for all three years in 1997 (the year the requirement was enacted). Id. In addition, the Joint Committee staff requested the Department of State to identify the number of approved CLNs [Certificate of Loss of Nationality] for each of these three years. The Department of State advised the Joint Committee staff that they are unable to provide a yearly breakdown of CLNs approved for the years 1995, 1996 and 1997. According to the Department of State, their prior practice of collecting statistics on the annual numbers of CLNs was discontinued in 1994 because it did not serve their specific needs.

So now we know what was going on: 1997 was three years of data compressed into one. 2011 does have the highest recorded number of renunciations in US history. So I've simply divided the 1997 renunciation data by three and spread it across the three missing years:

US Renunciations Per Year

That looks much better. So yes, 2011 was the highest number of expatriations ever recorded and it looks like the trend is holding. Clearly the number of renunciations has been holding steady and something has caused it to shoot much higher. Of course, we already know exactly why Americans are giving up their citizenship. Everything I read points to the same thing. However, I've had contact with two people who are telling me that the renunciation appointments at various consulates suggest much higher numbers than are being reported in the Federal Register. I have ideas on how to find those numbers, but I don't have the time. I'll give it more thought.