The defendants are appealing from a summary judgment favorable to the plaintiffs. The sole issue in this case is the construction of a tax escalation clause, Section 6 in a standard form commercial lease. We are asked to examine the so-called rent adjustment provision, which is set out in the margin,3 and to focus specifically on the phrase “in any one year.”

*525The plaintiffs (the lessees here) leased for a ten-year period, commencing February 1, 1982, certain space in premises at 167 Newbury Street in Boston from the lessors, two of whom are now deceased. On October 28, 1982, the plaintiffs entered into a second lease for additional space in the same premises. The second lease contains a rent adjustment clause based upon a certain percentage of any increase in the real estate taxes levied against the premises. The plaintiffs’ complaint sought a declaratory judgment that the effect of the clause was that the plaintiffs shall pay a maximum of $500 per year as their share of any real estate tax increase. Both parties moved for summary judgment.

Summary judgment is appropriate when there is “no genuine issue of material fact.” Mass.R.Civ.P. 56, 365 Mass. 824 (1974). The interpretation of the terms of an unambiguous lease is a question of law to be decided by the court. Great Atl. & Pac. Tea Co. v. Yanofsky, 380 Mass. 326, 334 (1980). The Superior Court judge concluded that the language in the clause was unambiguous and ruled that as matter of law “[S]ection 6 of the lease is declared to mean that [the] plaintiffs shall pay a maximum of $500.00 per year non-cumulative as the lessee’s share of any real estate tax increases.” The judge’s interpretation of the clause is correct.

The defendants contend that the judge erred by giving no effect to the words “in any one year” when she interpreted Section 6 to mean that the increase was noncumulative. They cite, as do the plaintiffs, Duane Realty Corp. v. Great Atl. & Pac. Tea Co., 8 Mass. App. Ct. 899 (1979), as the controlling case on this issue. In Duane, the court construed the word “annually” in another tax escalation clause to mean that the tax increase was not cumulative. The court in dicta suggested that if a cumulative increase were intended in a clause such *526as Section 6 then the parties would have to provide some language such as “said increase shall not exceed $500 in any one year over the last preceding year.” In so doing the court referred to two New York cases.4

The defendants contend that the clause at issue in this case and the one in the Oceantown case, cited in Duane Realty, are, as the Superior Court judge noted, similar. See Duane Realty Corp., 8 Mass. App. Ct. at 900. A close reading of the Oceantown case, however, reveals that the decision there that the increase was cumulative turned on the construction of the term “successive year,” not on the term “in any one year.” Oceantown Realty Corp. v. Great Atl. & Pac. Tea Co., supra at 503-504. Cf. Westbury Post Ave. Associates v. Great Atl. & Pac. Tea Co., 46 App. Div. 2d 860 (1974), aff’d, 38 N.Y.2d 890 (1976) (“previous year”). A clause containing language basing the increase on the prior year’s tax rate may be construed so as to operate cumulatively. See, e.g., Oceantown Realty Corp., supra at504. Contrast Duane Realty Corp., supra. However, where, as here, the clause fixes a base year tax — fiscal year 1981 — and tacks on a maximum annual liability of $500 in any one year, the additional rent is noncumulative. See and contrast Oceantown Realty Corp., supra. The judge correctly ruled that as matter of law the clause was not cumulative.

Deciding as we do, we find it unnecessary to credit or rely upon deposition testimony that two of the lessors, both now deceased, billed and accepted payments of $500 per year under the tax clause for the two years immediately preceding this dispute. Likewise, we see no need to comment on the plaintiffs’ assertion that the original parties to the lease intended that the amount to be paid each year was not to exceed $500.

Judgment affirmed.