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Annual trend in the number of published SRs and RCTs between 1990 and 2021. The number of RCTs significantly increased from 66 to 309 (25.8/month) over the periods (p for trend < 0.001). The number of SRs also significantly increased from 2 in 1990 to 519 (43.3/month) in 2021 (p for trend < 0.001)
