如何实现对数曲线的拟合

x={30,60,90,120,150,180,210,240,270,300,330,360,390,420,450,480,510,540,570,600,630,660,690,720,750,780,810,840,870,900,930,960,990,1020,1050,1080,1110,1140,1170,1200,1230,1260,1290,1320,1350,1380,1410,1440,1470,1500,1530,1560,1590,1620,1650,1680,1710,1740,1770,1800,1830,1860,1890,1920,1950,1980,2010,2040,2070,2100,2130,2160,2190,2220,2250,2280,2310,2340,2370,2400,2430,2460,2490,2520,2550,2580,2610,2640,2670,2700,2730,2760,2790,2820,2850,2880,2910,2940,2970,3000,3030,3060,3090,3120,3150,3180,3210,3240,3270,3300,3330,3360,3390,3420,3450,3480,3510,3540,3570,3600,3630,3660,3690,3720,3750,3780,3810,3840,3870,3900,3930,3960,3990,4020,4050,4080,4110,4140,4170,4200,4230,4260,4290,4320,4350,4380,4410,4440,4470,4500,4530,4560,4590,4620,4650,4680,4710,4740,4770,4800,4830,4860}
y={21.3999996821086,21.5433334986369,21.7766674041748,21.9333330790202,22.1000003814697,22.2566676457723,22.2933344523112,22.2933343887329,22.3166675567627,22.3633335113525,22.3733333587646,22.3433338165283,22.3333339691162,22.3033344268799,22.2933344523112,22.2966677983602,22.2900011062622,22.2966677983602,22.3000011444092,22.3633335113525,22.3966664632161,22.4366664250692,22.506666692098,22.5333334604899,22.6066670735677,22.6633339564006,22.7066674550374,22.7566676457723,22.8000011444092,22.8166674931844,22.8233341217041,22.8433338165283,22.8600002288818,22.8433338165283,22.8633335113525,22.8666667938232,22.8866664886475,22.8899997711182,22.8933330535889,22.8999996185303,22.8999996185303,22.8999996185303,22.9199996948242,22.9199996948242,22.9633331934611,22.9599998474121,23,23,23.0200000762939,23.0633335749308,23.0866669972738,23.1133337656657,23.1066670735677,23.1033337275187,23.1400005340576,23.1400005340576,23.1900007247925,23.2000007629395,23.2000007629395,23.2233341852824,23.2433342615763,23.2733343760173,23.2933344523112,23.3000010808309,23.3500003814697,23.3899997711182,23.3999996185303,23.3933330535889,23.3999996185303,23.3966663360596,23.3999996185303,23.3999996185303,23.4099996566772,23.4066663106283,23.4233330408732,23.4599998474121,23.4733332316081,23.493333307902,23.496666653951,23.503333346049,23.510000038147,23.5333334604899,23.5300001144409,23.5400001525879,23.5866669972738,23.6200004577637,23.6233338038127,23.6433338801066,23.6433338801066,23.6766673405965,23.6900007247925,23.6966674168905,23.7000007629395,23.6933340708415,23.7000007629395,23.7000007629395,23.7066674550374,23.7033341089884,23.7100008010864,23.7033341089884,23.7200008392334,23.7100008010864,23.7366675694784,23.7433342615763,23.7833344141642,23.810000928243,23.8000010808309,23.8066677093506,23.813334274292,23.8200008392334,23.8233341217041,23.8500003814697,23.8899997711182,23.8799999237061,23.8999996821086,23.8999996821086,23.9066663106283,23.8999996185303,23.9133330027262,23.9399997711182,23.9433331171672,23.9399997711182,23.9633331934611,23.9766665776571,23.993333307902,24.003333346049,24,24.003333346049,24.003333346049,24.003333346049,24.006666692098,24.0233334223429,24.0200000762939,24.0466668446859,24.0700002670288,24.0933336893717,24.0933336893717,24.1000003814697,24.1033337275187,24.1100004196167,24.1066670735677,24.1200004577637,24.1200004577637,24.1500005722046,24.1633339564006,24.1900007247925,24.1866673787435,24.1966674168905,24.1966674168905,24.2000007629395,24.2000007629395,24.1900007247925,24.1966674168905,24.2000007629395,24.2000007629395,24.2200008392334,24.2233341852824,24.2133341471354,24.2133341471354,24.2400009155273,24.2600009918213,24.2800010681152,24.2833344141642,24.2900011062622,24.3033344268799,24.3000010808309,24.310000928243,24.3000010808309,24.3100009918213,24.3300006866455,24.3266674041748,24.3300006866455,24.3500003814697,24.3300006866455,24.3566669464111,24.3733333587646,24.3866664886475,24.3866664886475,24.3799999237061,24.3933330535889,24.3933330535889,24.3999996185303,24.3999996185303,24.3999996185303,24.3966663360596,24.4033329645793,24.3999996185303,24.4033329645793,24.4033329645793,24.4099996566772,24.4133330027262,24.4033329645793,24.4033329645793,24.4233330408732,24.4099996566772,24.4266663869222,24.4499998092651,24.4299997329712,24.4533331553141,24.4766665776571,24.4633331934611,24.4633331934611,24.5,24.5,24.510000038147,24.513333384196,24.513333384196,24.513333384196,24.5200000762939,24.506666692098,24.5200000762939,24.5233334223429,24.51333338419}给定一组数，如何实现对数曲线Y=Kln(x)+B的拟合？？高手指点！！！