P11, P8 and P9 do not seem to exist in the dataset.
Can you explain i substantive, subject matter, terms what you want to do.
Is this the dataset you wish to work with?
MYdata)
structure(list(DATE = c("01/04/2017", "01/07/2017", "01/08/2017",
"01/09/2017", "01/10/2017", "01/11/2017", "01/03/2018", "01/08/2018",
"01/11/2018", "01/12/2018", "01/01/2019", "01/03/2019", "01/05/2019",
"01/06/2019", "01/10/2019", "01/02/2020", "01/04/2020", "01/05/2020",
"01/07/2020", "01/10/2020", "01/02/2021", "01/03/2021", "01/05/2021",
"01/08/2021", "01/09/2021", "01/12/2021", "01/01/2022"), I1 = c(500,
520, 700, 660, 560, 876, 720, 733, 600, 588, 576, 564, 552, 540,
528, 516, 504, 492, 480, 471, 488, 550, 600, 690, 610, 645, 699
), I2 = c(700, 550, 523, 622, 622, 622, 726, 700, 720, 695, 670,
645, 620, 595, 570, 545, 520, 660, 662, 664, 666, 668, 670, 672,
489, 491, 493), I3 = c(990, 910, 950, 857, 770, 1088, 600, 750,
582, 810, 577, 610, 643, 676, 709, 742, 775, 808, 841, 874, 907,
940, 973, 1006, 1039, 1000, 988), I4 = c(24, 500, 248, 500, 870,
100, 152, 44, 172, 128, 655, 155, NA, NA, NA, NA, NA, NA, NA,
NA, NA, NA, NA, NA, NA, NA, NA), I6 = c(800, 1250, 998, 651,
651, 651, 1100, 1000, 1250, 1302, 1220, 1302, 1302, 1200, 1115,
1025, 1250, 1283, 651, 651, 651, 651, 651, 778, 769, 810, 888
), I10 = c(4000, 4200, 4300, 4351, 3300, 3210, 2000, 2500, 3300,
4351, 4150, 4000, 4050, 3900, 3750, 3600, 2200, 2150, 1922, 1955,
1954, 1900, 1899, 1886, 1920, 1990, 2100), I13 = c(3669, 3644,
3590, 3602, 3577, 3523, 3535, 3510, 3456, 3468, 3443, 3389, 3401,
3376, 3322, 3334, 3309, 3255, 3267, 3242, 3188, 3200, 1552, 1552,
1527, 1473, 1485), I14 = c(2595, 3000, 3000, 3098.48, 3071.48,
3044.48, 3017.48, 2990.48, 2963.48, 2936.48, 2909.48, 2882.48,
2855.48, 2828.48, 2801.48, 2774.48, 2500, 1721.23, 1765.23, 1809.23,
1853.23, 1897.23, 1941.23, 1985.23, 2029.23, 2073.23, 2500),
I15 = c(19932.86, 19722.86, 19512.86, 19302.86, 19092.86,
18882.86, 19000, 18462.86, 19015, 18042.86, 17832.86, 17622.86,
17555, 17202.86, 16992.86, 17005, 16572.86, 8931.76, 9000,
8999, 8900, 8756, 8900, 19932.86, 8931.76, 8999, 9000), I16 = c(8650.44,
8650.44, 8650.44, 8650.44, 8650.44, 7500, 7250, 8650.44,
7450, 8650.44, 6000, 5100, 5500, 8650.44, 4999, 4969, 4939,
4909, 4879, 4849, 4819, 4789, 4759, 4729, 4699, 4659, 4654.94
), I18 = c(2620.47, 2596.47, 2572.47, 2548.47, 2524.47, 2500.47,
2476.47, 2452.47, 2428.47, 2404.47, 2380.47, 2356.47, 1340,
1340, 1340, 1340, 1361, 1382, 1403, 1424, 1445, 1466, 1487,
1340, 1361, 1382, 1403), I19 = c(40, 39.2, 37.8, 32, 31,
41.92, 36.92, 31.92, 26.92, 21.92, 16.92, 19.92, 22.92, 25.92,
28.92, 31.92, 34.92, 33, 33, 32.8, 31.9, 15.15, 22, 21, 29,
33, 35)), class = "data.frame", row.names = c(NA, -27L))