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We have analyzed the parsec-scale jet kinematics of 447 bright radio-loudAGN, based on 15 GHz VLBA data obtained between 1994 August 31 and 2019 August4. We present new total intensity and linear polarization maps obtained between2017 January 1 to 2019 August 4 for 143 of these AGN. We tracked 1923 brightfeatures for five or more epochs in 419 jets. A majority (60%) of thewell-sampled jet features show either accelerated or non-radial motion. In 47jets there is at least one non-accelerating feature with an unusually slowapparent speed. Most of the jets show variations of 10 to 50 deg in their innerjet position angle (PA) over time, although the overall distribution has acontinuous tail out to 200 deg. AGN with SEDs peaked at lower frequencies tendto have more variable PAs, with BL Lacs being less variable than quasars. TheFermi LAT gamma-ray associated AGN also tend to have more variable PAs than thenon-LAT AGN in our sample. We attribute these trends to smaller viewing anglesfor the lower spectral peaked and LAT-associated jets. We identified 13 AGNwhere multiple features emerge over decade-long periods at systematicallyincreasing or decreasing PAs. Since the ejected features do not fill the entirejet cross-section, this behavior is indicative of a precessing flow instabilitynear the jet base. Although some jets show indications of oscillatory PAevolution, we claim no bona fide cases of periodicity since the fitted periodsare comparable to the total VLBA time coverage.

MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies