I think this is what you could be looking for...The stats are dated 2001, World Christian Trends, William Carey Library, David Barrett and Todd Johnson:
*Note percentages are of world population
My interpretation of the data below for the decade of 1990-2000 indicates that if total increase rates of the religion are taken into consideration then Islam would be growing faster than Christianity with a rate of 2.13 annual change for Islam and 1.36 annual change for Christianity. However, a close study of the data would indicate that Islam has a large number of adherents which are added to the faith by natural birth. Therefore, if one were to look solely at the conversion rate Chrsitianity would be the fastest growing religion, more than tripling Islam in its annual conversion rate.
Besides the Independents, Pentecostals/Charismatics seem to be the fastest growing Christian sect for that period. Catholicism suffered big losses.
Animists and Shamanists suffered the biggest losses.
Hindus also suffered big losses as well as Atheists, Nonreligious, Jews and various Asian religions.
Christians: 558,131,572 = 34.5% (Orthodox: 115,844,210 = 7.2%)
Muslims: 199,940,924 = 12.3%
Christians: 1,236,373,744 = 33.5% (Orthodox: 139,661,574 = 3.8%)
Muslims: 553,527,803 = 15.0%
Christians: 1,747,461,964 = 33.2% (Orthodox: 203,765,600 = 3.9%)
Muslims: 962,357,235 = 18.3%
Annual change, 1990—2000
Christians: Natural=22,708,799 Conversion=2,501,396 Total=25,210,195 Rate=1.36
(Orthodox: Natural=750,901 Conversion=385,410 Total=1,136,311 Rate=0.54)
Muslims: Natural=21,723,118 Conversion=865,558 Total=22,588,676 Rate=2.13
Christians: 1,877,425,923 = 33.1% (Orthodox: 209,624,412 = 3.7%)
Muslims: 1,070,198,775 = 18.9%
Christians: 1,999,563,838 = 33.0% (Orthodox: 215,128,717 = 3.6%)
Muslims: 1,188,242,789 = 19.6%
Christians: 2,616,670,052 = 33.4% (Orthodox: 252,715,940 = 3.2%)
Muslims: 1,784,875,653 = 22.8%
Christians: 3,051,564,342 = 34.3% (Orthodox: 266,806,050 = 3.0%)
Muslims: 2,229,281,610 = 25.0%