lower estimates put forth by "revisionist" scholars. Simon Sebag Montefiore in 2003 suggested that Stalin was ultimately responsible for the deaths of at least 20 million people. Some of these estimates rely in part on demographic losses. Conquest explained how he arrived at his estimate: "I suggest about eleven million by the beginning of 1937, and about three million over the period 1937–38, making fourteen million. The eleven-odd million is readily deduced from the undisputed population deficit shown in the suppressed census of January 1937, of fifteen to sixteen million, by making reasonable assumptions about how this was divided between birth deficit and deaths." Some historians also believe that the official archival figures of the categories that were recorded by Soviet authorities are unreliable and incomplete. In addition to failures regarding comprehensive recordings, as one additional example, Canadian historian Robert Gellately and British historian Simon Sebag Montefiore argue that the many suspects beaten and tortured to death while in "investigative custody" were likely not to have been counted amongst the executed.Conversely, Australian historian Stephen G. Wheatcroft asserts that prior to the opening of the archives for historical research, "our understanding of the scale and the nature of Soviet repression has been extremely poor" and that some specialists who wish to maintain earlier high estimates of the Stalinist death toll are "finding it difficult to adapt to the new circumstances when the archives are open and when there are plenty of irrefutable data" and instead "hang on to their old Sovietological methods with round-about calculations based on odd statements from emigres and other informants who are supposed to have superior knowledge". Remembering the victims A Day of Remembrance for the Victims of Political Repression (День памяти жертв политических репрессий) has been officially held on 30 October in Russia since 1991. It is also marked in other former Soviet republics with the exception of Ukraine, which has its own annual Day of Remembrance for the victims of political repressions by the Soviet regime, held each year on the third Sunday of May. Members of the Memorial society have taken an active part in such commemorative meetings. Since 2007 Memorial has also organised the day-long "Restoring the Names" ceremony at the Solovetsky Stone in Moscow every 29 October. The Wall of Grief in Moscow, inaugurated in October 2017, is Russia's first monument ordered by presidential decree for people killed during the Stalinist repressions