Checking internal consistency of data and removing outliers

How do I check the internal consistency of a dataset, find and remove outliers. When I plot the data, the outliers are already visible (see diagram)

The sample dataset is attached below.

2077 1972-01-06 0.9677650
2078 1972-01-07 0.9613600
2079 1972-01-08 0.9573950
2080 1972-01-09 0.9183550
2081 1972-01-10 0.9113400
2082 1972-01-11 0.9235400
2083 1972-01-12 0.9503800
2084 1972-01-13 0.9808800
2085 1972-01-14 NA
2086 1972-01-15 1.0002983
2087 1972-01-16 1.0046700
2088 1972-01-17 0.9946812
2089 1972-01-18 0.9966383
2090 1972-01-19 NA
2091 1972-01-20 1.0115325
2092 1972-01-21 1.0284600
2093 1972-01-22 1.0142775
2094 1972-01-23 1.0110750
2095 1972-01-24 1.0381183
2096 1972-01-25 1.0739050
2097 1972-01-26 NA
2098 1972-01-27 NA
2099 1972-01-28 NA
2100 1972-01-29 1.0736000
2101 1972-01-30 1.0633825
2102 1972-01-31 1.0590108
2103 1972-02-01 1.0696350
2104 1972-02-02 1.0839700
2105 1972-02-03 1.1861450
2106 1972-02-04 1.3607067
2107 1972-02-05 1.3563350
2108 1972-02-06 1.3490150
2109 1972-02-07 1.3582870
2110 1972-02-08 1.3459650
2111 1972-02-09 1.3405970
2112 1972-02-10 1.3407800
2113 1972-02-11 1.3352900
2114 1972-02-12 1.3359000
2115 1972-02-13 1.3333075
2116 1972-02-14 1.3323925
2117 1972-02-15 1.3383400
2118 1972-02-16 1.3370183
2119 1972-02-17 1.3416950
2120 1972-02-18 1.3435250
2121 1972-02-19 1.3429150
2122 1972-02-20 1.3217175
2123 1972-02-21 1.3473883
2124 1972-02-22 1.4033050
2125 1972-02-23 NA
2126 1972-02-24 NA
2127 1972-02-25 1.3997467
2128 1972-02-26 1.4042200
2129 1972-02-27 1.4013225
2130 1972-02-28 1.4030000
2131 1972-02-29 1.4176400
2132 1972-03-01 1.4222150
2133 1972-03-02 1.4328900
2134 1972-03-03 NA
2135 1972-03-04 1.4321275
2136 1972-03-05 1.4249600
2137 1972-03-06 NA
2138 1972-03-07 NA
2139 1972-03-08 NA
2140 1972-03-09 1.4332967
2141 1972-03-10 1.4636950
2142 1972-03-11 1.4823000
2143 1972-03-12 1.4826050
2144 1972-03-13 1.4978550
2145 1972-03-14 NA
2146 1972-03-15 1.5063187
2147 1972-03-16 1.5201200
2148 1972-03-17 NA
2149 1972-03-18 1.52271

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