As I detail below, this is a question that is hard to answer with certainty, as much of the data is not recorded (or was never taken in the first place). It would seem that in the 90s, a plausible figure could be roughly 10 landmine incidents per year in the Kyiv area. Is that enough for treading on a mine to be an common occurrence? I would say yes, but obviously this is a personal matter.
From an edition of the Landmine and Cluster Munition Monitor from 2007 (predating the current Ukraine-Russia hostilities, but slightly later than the desired time-period of the 1990s), it is noted that:
Ukraine is contaminated with antipersonnel mines and explosive
remnants of war. The contamination results mainly from heavy
fighting between German and Soviet forces in World War II, also from
World War I, the 1917-1921 civil war and the Cold War. The scope
of the mine problem has not been precisely identified. In its two
Article 7 reports Ukraine has declared that there are no known or
suspected areas containing antipersonnel mines under its jurisdiction
or control. However, mines continue to be discovered; for example,
on 14 July 2007, among other World War II munitions, two landmines
were discovered in a field near Kupyansk City.
The article goes on to give further data on the number of casualties:
The total number of mine casualties in Ukraine is not known with
certainty... Between 2000 and 2006 Landmine Monitor recorded 92
mine/ERW casualties (45 killed and 47 injured).
This gives an average rate of 15 casualties a year, although for the whole country as opposed to just the Kyiv area. An appendix to a report by the US State Department, Appendix F: "Hidden Killers 2001-- The World's Landmine Problem" indicates that Kyiv is one of the minefield hotspots, as could be expected since it was one of the major areas of combat in the Second World War:
Since 1945, landmines and UXO have killed an estimated 1,800 people,
including Explosive Ordnance Disposal personnel. Although UXO is found
throughout the country, most of it is in the Crimea, (perhaps 100,000
tons in Sevastapol and Kerch alone), Odessa, Dnepropetrovsk, Vinnitsa,
Ternopol, Zhitomir, Kiev, and Kharkiv.