We ended 2022 with ARR of $1.037 billion at year-end spot rates, now for the first time above $1 billion, and our constant currency ARR growth rate was 15%. Power Line Systems onboarded 2.5% of this growth and our business performance accounts for the remaining 12.5%, which is the midpoint of our financial outlook range. The strong and sustained momentum of our business performance is driven by our E365 and SMB growth initiatives and the continued growth velocity of our platform acquisitions of Seequent and Power Line Systems, making up for lost ARR in Russia and headwinds in China. Our last 12 months recurring revenues at actual currencies increased by 17% year-over-year. The acquisition of Seequent and Power Line Systems contributed about 11 percentage points of this improvement.
Our GAAP operating income was $41 million for Q4, down $3 million and $209 million for the full year, up $114 million year-over-year. We have previously explained the impact on our GAAP operating results from acquisition costs, incremental amortization from purchased intangibles, increases in stock-based compensation and the onetime accounting charge for deferred compensation of approximately $91 million in 2021. Moving on to adjusted EBITDA, our fourth quarter grew by approximately 5% over 2021 Q4 and our full year adjusted EBITDA of $366 million is an improvement of approximately 13%. With an adjusted EBITDA margin of 33.3%, we delivered on our 2022 adjusted EBITDA margin commitment of about 100 basis points margin improvement over our normalized adjusted EBITDA margin of 32.3% in 2021.
As you will remember, in 2020 and 2021, we normalized our margin performance for temporary margin windfalls from reduced travel and events. In 2022, travel and events are now in line with what we believe to be a normalized post-pandemic run rate. Greg already described that starting in 2023, we will measure our operating margin performance and improvements the same way for our annual outlook as we will do for purposes of executive incentives which will be based on adjusted operating income, inclusive of stock-based compensation. We believe that this measure appropriately captures the true economic cost of shareholder dilution from stock-based compensation. It also includes operating depreciation and amortization, which will increase as our CapEx will include digital experience IT investments of approximately $10 million in 2023 and a comparable amount in 2024.
With respect to liquidity, our Q4 operating cash flow of $36 million decreased 55% and our full year operating cash flow of $274 million decreased by 5% year-over-year. We have previously discussed that our business model produces reliable and efficient cash flows over a trailing 12 months period, but with some variability between quarters. We have no significant upfront multiyear collection, which limits variability on a trailing 12 months basis. And our continued expansion of our E365 program, where we collect the deposit for the estimated annual consumption at the onset of the annual contract period generates strong cash flows. However, our 2022 Q4 and full year cash flows were impacted by a shift in billing and therefore collections of certain E365 renewals and newly converted E365 contracts, all representing healthy new business.
